For those that don't mind trading a 15 min prep time for a much lower feed bill, homemade steamed egg is a great food for feeding new goldfish (or to balance out one of the above foods. Our recipe is based on one that we learned from Gary Hater at The Goldfish Council, and it works very well!
At any rate, let's explore that first question together now; what's the best food to feed your goldfish to get the best growth?
Why Is Feeding Goldfish So Complicated?!?
If you're a caring goldfish owner and are overwhelmed by the choices available to feed your fish today, I can totally relate. I still remember looking through those shelves of colorful fish foods at my local aquarium store, completely bewildered at why I would choose one vs the other.
If you're in a rush, I've provided a few quick recommendations above. If you want a more in depth answer, you'll find those using one of the links in the table of contents below.
At any rate, the best thing you can do is arm yourself with knowledge, and not make knee jerk choices simply out of fear of something you've read online somewhere.
When you know the reasons behind the choices you make, it becomes easier to see through the sales pitches to the actual truth inside.
Floating Vs Sinking: What's Better For Goldfish Food
One of the most popular sayings among goldfish owners is to never feed floating foods, since that will cause them to gulp air and get swim bladder issues.
It's understandable that people might want to connect gulping air with getting "floaty", but unfortunately the biology just doesn't support it.
In fact, when we hatch newborn goldfish babies, we make sure to keep them in very shallow water so that their first trip to the surface doesn't take very long. If they can't do that, their swim bladders sometimes don't develop properly and they sit on the bottom of the tank permanently.
Muscles which surround the swim bladders allow the fish to regulate how much air stays in the bladders, and how much of a tendency to sink or swim the fish will have. Rather than being something the fish has to live with passively, goldfish can control the inflation level in their swim bladders if all is going well.
As a result, being concerned about fish getting food from the surface isn't something you need to worry about. Yes, they'll take in a bit of air, but if they want to get rid of it they're more than capable of doing so.
In fact, many koi keepers and goldfish pond owners intentionally feed floating pellets to better keep track of how much each fish is eating, and to make sure each fish is feeling well enough to eat.
Koi happily eating pellets from the surface of the pond
It's only when the fish is sick, or its ability to operate the muscles around the swim bladder is compromised, that they start to have issues with being "floaty".
The cause for this isn't well documented or understood in the general hobby, but I was lucky enough to hear a talk by Hikari USA President Chris Clevers at Goldfish Palooza 2018 that provided some research to back up some of the practical things we'd found in managing goldfish and swim bladder issues.
Hikari Research Into Swim Bladder Issues in Goldfish
First off, if you weren't aware already, rather uniquely in the fish food market Hikari manages a huge research operation at Yamasaki Koi Farm in Japan. There they not only do research into foods for their own lineup, but they actively test the foods of their competitors both in the lab and by using it to raise fish from birth to maturity using that food.
In the face of increasing demand from the market for sinking rather than floating foods, Hikari set out to try to find a link between these styles of food and swim bladder issues.
Exactly as they suspected, their scientists could find no link between swim bladder problems and floating foods.
The things they did identify as issues were:
foods that pass slowly through the gut, blocking openings to the swim bladder
bacterial infections in the swim bladder resulting from either poor nutrition or obstruction of the bladder due to poor gut function from those foods
bad water quality due to poor maintenance practices (buildup of waste in the water and in the tank environment leading to increased bacterial activity)
So although they haven't made these findings available to the public (believe me, I asked a few times!), they do back up what we as breeders have found. Namely, that clean water, good quality food, and the careful application of antibiotics if required tend to be the best ways to prevent or help relieve swim bladder issues.
How Can I Help Prevent My Goldfish From Getting Swim Bladder Problems?
In a nutshell, the best ways to make sure your goldfish doesn't go floaty on you are to:
make sure you're keeping up on your maintenance. Keep your water clean (0 ammonia, 0 nitrite, <40ppm nitrate), use your gravel vacuum as needed, and clean your filter in old tank water when you do your water changes
feed foods that contain quality ingredients. We'll get into what that means very shortly in this article
periodically change up your foods to see that the color of the goldfish's poop changes within a day of doing so. Feeding homemade steamed egg using our adaptation of Gary Hater's recipe is an option, and the white poop it produces is easy to see and passes quickly. Making sure that the digestive system isn't moving slowly makes sure the fish don't get stopped up and constipated, which can cause bacteria levels to build up in the gut and swim bladder
With a simple and solid ingredients list (whole salmon, whole shrimp, wheat flour, wheat gluten, fresh kelp) that reads like proper food and with only enough binders to actually make it into flake form (the wheat parts), this food defies the usual logic that flake food is inherently low quality.
With flake food being what that most of us remember using as our initiation into fish keeping, the direction to "feed a pinch of flake a few times a day" feels as warm and classic as just about anything else in the fish keeping hobby.
In fact, although most flake foods tend to be made of low quality ingredients and marketed towards people that shop by price more than anything else, it's actually possible to buy flake foods that contain decent ingredients nowadays.
Flake is even one of the best ways of dosing certain medications for a lot of people, since most medicated foods you can buy tend to be flake foods (the medicine being most easily absorbed by the thin flake). Especially for things like deworming medications which are most effectively dosed by ingesting them (assuming the fish is well enough to eat), this is a useful purpose for flake foods even for people that choose other styles of food normally.
That all said, even aside from the issues with finding a quality flake food (most are mainly fillers and binders), the flake format has some inherent limitations.
Given that flake is quite a light and airy food, even quite a large container rarely actually contains a significant weight of food compared to more densely packed pellets or gel powder. As a result of this, you'll find yourself going through cans of flake food quicker than a similar size of pellet if you're feeding the same weight of food. Counter-intuitively, this can actually make flake food quite a bit more costly in the long run.
The same weight of food measured out for hydrated gel, pellet, and flake food. Most people tend to underfeed flake and overfeed pellets as a result
Feeding enough flake can cause you to run through those cans of flake surprisingly quickly!
Additionally, although the thin and largely water soluble format of flake means that the goldfish doesn't have to contend with a dry, solid lump of food passing through their digestive system (a good thing), it does mean that flake tends to lose its water soluble vitamins and nutrients quicker than other, more water-stable forms of food.
As a result of this, more than any other format flake benefits from being fed more often and in smaller quantities than other formats. It actually gets better absorption in the gut due to the high surface to volume ratio, so the frequent feedings will have a positive benefit. Ideally the fish should be able to finish their meals quickly in order to gain the maximum benefit from the food as quickly as possible.
Having a very high surface area to volume ratio, it also oxidizes far more quickly than other styles of food (loses nutritional value), so make sure to try to feed out flake food within three months of opening it (or from the packing date, if listed).
In the end though, although there are some solid choices in this category that could be easily fed long-term (particularly as part of a rotation with other foods), most experienced goldfish keepers tend to move on to different formats for food after a while to get access to higher quality nutritional ingredients.
Erica and I go through a lot of food growing out our goldfish babies, and one of our favorite foods when they're ready for more solid foods is Northfin. Great ingredients, good price, and made right here in Canada.
Up here in Canada this is a little too expensive to feed as the primary food for our fish in the quanitity we need to, but we still use it for certain breeds (mainly ranchu) for the amazing results it yields in head growth and body development.
One of the few excellent foods with a largely unimpressive ingredient label, but yields growth results that are hard to argue with.
For most goldfish owners, pelleted foods form the bulk of what they feed to their fish on a regular basis.
It's not hard to see why, either.
Pellets are convenient, are usually available in at least one formulation with the best ingredients a food supply company has available, and tend not to foul the water as easily as large amounts of flake food can.
Stored properly in the fridge (almost all fish foods contain oils and fats that will eventually spoil) pellet foods can last a long time, and can provide the bulk of what a goldfish needs to develop properly and healthily.
Pellet foods are also the easiest style of food to use with an autofeeder, for those that want to get the best and quickest growth from their fish. Studies have shown that breaking your fish's daily food portion into as many portions as possible spread throughout the day yields better growth (and fewer health problems) than a single large feeding.
Breeders have proven that to get the best growth out of our fish, we need to feed as many times a day as we can.
Since most people aren't able to feed more than a couple of times each day by hand, this is a perfect way to keep feeding your fish even when you're at work.
This model has proven to be one of the most (only?) reliable ones in terms of dispensing a consistent of food, not getting clogged, and not overfeeding.
Best used with pellet foods.
Although they can seem like the perfect food, pellets should still be carefully chosen to avoid falling into the trap of thinking that all pellets are created equally.
Although all dry foods require some form of binding filler agent in order to maintain their shape and form, care should be taken to make sure that not too much of the food ingredient label is made up of non-nutritional binding agents (usually wheat or some other grain).
Excessive amounts of binders and fillers reduce the price of a food, but can also result in a food that has an extremely long feed-through time. Feed through time is the time it takes for food to go in the mouth end of the fish and emerge out the other end in digested form.
The slower that process goes, the greater the chance of constipating the fish (preventing it from expelling waste), and the more likely the fish is of having gut and swim bladder bacterial levels building up and causing buoyancy or swim bladder problems.
Good quality pellets should never cause these issues, but lower quality pellets can sometimes benefit from the addition of fresh vegetables or more digestible foods (gels or homemade foods) to help speed things along the bowel.
Since pelleted foods represent highly concentrated nutrition, and especially with less expensive varieties that contain lower quality ingredients, care should be taken not to overfeed pellets. Doing so can cause gut issues, and may lead to obesity, fatty liver issues, and a host of other problems.
Goldfish Live, Frozen and Freeze-Dried Food: Single Ingredient Foods
This class of foods tends to be what we'd call "single ingredient" formulations. That's not to say that these foods don't have a variety of nutritional benefits, but more that they only come from one food source ingredient (ie, bloodworms, blackworms, daphnia etc).
As a result of this, most live, frozen and freeze dried foods shouldn't be the only food you feed to your goldfish, but given as a supplement or a treat in addition to some other, more nutritionally balanced food.
Most of these foods are available in both frozen and freeze dried form, so before going into the benefits of each ingredient let's take a look at each style of food broadly.
Frozen Foods For Goldfish
Although the awkwardness of transporting frozen foods by mail usually means that those foods have to come from your local fish store, frozen foods are an extremely high quality way of feeding your fish.
Frozen foods can come as either small blister packs with neatly spaced and portioned bubbles, or (usually less expensively) as frozen sheets with no divisions.
As with anything, there are many long-time arguments for how to properly feed frozen foods.
Some people will thaw the food before feeding it, and others throw the food straight into the tank.
The advantages of throwing the food into the tank frozen are:
convenience, and not having to wait for the food to thaw
the frozen food acts like a slow-feeder, slowly dispensing food as it melts. This can help less assertive fish get a portion in a crowded tank
you have the option of straining off the "juice" and not including that with the feed (can contribute in minor ways to nitrate levels)
it feels less like you're giving your fish "brain-freeze", though none have ever had issues with frozen food in my experience
I tend to cut my blister trays into portions, thaw them in a bowl of water, then feed that way. The only reason I do that is to spread the foods between tanks, and to have the flexibility to give very young fish small targeted portions.
Freeze Dried Foods For Goldfish
For those without a good local fish store to turn to, or for those to whom cost or storage convenience is more of an issue, freeze dried versions of most frozen foods are available as well.
As with frozen foods, there's quite a bit of debate as to how best to prepare these foods.
Some folks feed right into the tank, others rehydrate the food with a little water beforehand. I take the third option of adding them in to my homemade food recipes, which takes care of most of the hydration issues.
As a word of warning, some people can develop quite severe allergic reactions to freeze dried foods. It may just be a coincidence, but I've heard of this happening more so with freeze dried foods than any other (maybe the dust is a particular issue for some people?). I've never had any issues myself, but it's something to at least be aware of.
Live Foods For Goldfish
For the most part, goldfish keepers that intentionally purchase or culture live foods for their fish tend to be in the minority. The reason for that tends to be both cost and the hassle of the extra work involved.
That said, when it comes to providing nutritional value, it's hard to argue with live foods.
Most commonly available to goldfish keepers are micro foods for baby fish like:
baby brine shrimp (in the form of eggs that need hatching)
We feed an absolute ton of live brine shrimp to our baby goldfish, and they positively thrive because of it. We also use microworms a lot as they get older because microworms are a cheap and nutritious food source, but just make sure that they're part of a complete diet and not only thing you feed or your fry may not develop properly.
Foods that work for bigger fish are things like:
Daphnia ponds and harvested daphnia in particular are what most goldfish raised in tropical climates mainly live on, since those countries don't have access to expensive brine shrimp eggs with the same level of convenience as we do in North America.
Mosquito larvae can be captured on your own with a bucket of stagnant water in the backyard if you're careful not to let the neighbors know what you're doing, and live blackworms can be imported by most good fish stores that might also be your source of frozen foods.
As a somewhat controversial practice aimed partially at convenience and partially at cost savings, some breeders both domestically and overseas will feed cull goldfish fry back to their parents.
I don't do that in our hatchery largely out of inherent dislike of the practice, but also since logically goldfish are no better feeders for other goldfish than they are for non-goldfish species.
After all, goldfish are not only extremely fatty and high in copper sulfate, but they also contain an enzyme called thiaminase. Excessive consumption of thiaminase blocks thiamine absorption in the predator, and over time can cause neurological problems in the animal.
I have no idea if this can cause the same issue when fry are fed to adult goldfish, but I have no particular desire to find out either.
Brine Shrimp For Goldfish
The introduction of brine shrimp and brine shrimp eggs into the hobby decades ago marked the start of keepers being able to easily keep and breed a lot of challenging species.
While goldfish babies are less challenging than some pickier species of fish to raise, keeping and raising live baby brine is nonetheless a staple of most breeders' operations.
Preparing baby brine shrimp is an article in and of itself, but the short version is that it requires heat, light, salt water and a setup like this to get started:
A simple brine shrimp hatchery kit that you assemble yourself with the help of a 2L pop bottle.
Not the sturdiest thing in the world, and you'll still need an air pump and salt, but if you only need to raise a small batch of shrimp to feed a single spawn it'll do the job.
If you're able to get frozen brine shrimp, you may even have access to gut-loaded spirulina brine shrimp. That's brine shrimp that's been fed a heavy diet of spirulina algae, which in appropriate doses is extremely beneficial to the health of goldfish.
Daphnia (or Water Fleas) For Goldfish
Daphnia are one of the most commonly used foods overseas to grow healthy and gorgeous goldfish, yet one of the least appreciated ones here in North America.
That's a shame, because we've seen great results using them in our feeding program. In fact, next summer we plan to setup an outdoor culturing tub, and hopefully make this an even larger part of our feeding plan.
Like brine shrimp, daphnia have the same nutritional benefits combined with the bulk shell content to help heavier pellet or flake foods move through the digestive tract.
Unlike brine shrimp which are native to a marine (ocean) environment and must be rinsed before feeding and die within hours if uneaten in fresh water, daphnia are a native freshwater creature and have no such limitations.
As a result, almost unlimited quantities can be fed to a goldfish tank, with the goldfish able to take their time hunting down the daphnia with no risk of the daphnia dying and fouling the water.
Freeze dried daphnia is a great option for people who want an inexpensive but nutritious option to add to their goldfish feeding program.
Bloodworms For Goldfish
It's hard to say enough good things about feeding bloodworms to goldfish.
As with most good things it's possible to overdo feeding them (creating nutritional deficiencies in some areas and making the fish obese), but fed in moderation by the average owner a few times a week you're likely to see nothing but benefits to your fish's development and health.
Bloodworms are one of the most famous whole-food additions to goldfish diets, and for good reason. This freeze dried versioncombines all the health benefits in a stable version that's easy to store.
Blackworms For Goldfish
Freeze dried blackwormsare a convenient version of a food that's legendary for bringing fish into spawning condition. The hassle of sourcing and storing live worms makes this an attractive alternative to buying in-store.
Although this isn't a food I've had the chance to play with yet, it's one that I plan to use at some point.
Lots of breeders absolutely love black worms to bring fish into spawning condition (especially discus), and black worms are one of the few live foods that are relatively common in well-stocked aquarium stores.
If your store won't stock the live version due to worries about disease (they may be confusing these with tubifex worms), freeze dried options provide most of the same benefits.
As a result, though I have no personal experience to share with you, if you have a chance to pick some live or freeze-dried blackworms up at a reasonable price I'd highly encourage you to do so.
Tubifex Worms For Goldfish
Live tubifex worms are very rare in the hobby nowadays because of the disease-carrying potential of worms exposed to certain human diseases, but those risks aren't found in this freeze dried version according to Hikari
Tubifex worms used to be much more commonly available in the hobby in North America, but due to concerns with them being able to carry diseases which can be transmitted to humans, it's very rare to find the live version anymore (they're still used extensively in Thailand and other countries).
For those still wanting the nutritional value that tubifex worms provide (they're used for a reason, after all), the freeze dried products offered by Hikari in particular offer a disease-free option that can be fed without the risks described above.
Goldfish Gel Food
Making up gel food only take a minute, and will be appreciated by your fish!
If you had to pick only a single food to feed to your goldfish, you wouldn't do badly choosing Repashy's Supergold gel food as that food.
Gel food is made by taking the powder they ship you and either adding hot water to it, or adding cold water and microwaving it. Cooled gel food can be reactivated (melted) by heating it again, and some people even have fun with it by spreading it on rocks or wood as a "grazing treat" for their goldfish.
You can even turn making up food into an "enrichment activity" for your fish!
Gel food is incredibly useful for a number of reasons:
you can easily add medications to it as it cools (avoid doing so right away to minimize damage to the medication)
you can add things to it like pellets or the freeze dried foods above, making sure everything gets hydrated before feeding it to your fish
you can make and freeze it for later use with some blends
you can mix and match powder blends before activating to get some of the benefits of both
it's easily cut into portions appropriate for both big and little fish
for young fish you can feed larger portions that they can nibble on all day, since the gel makes the food pretty stable in water
Since Repashy is the king of gel foods nowadays, other than some homemade mixes I'll talk about shortly the mixes we use most of are listed below (in rough descending order of how much I use around here):
It's hard to love this product more, to be honest.
Formulated for goldfish specifically by one of the most respected names in the North American goldfish hobby (Ken Fischer of Dandy Orandas), this food is one of the finest options for hobby staple foods out there today.
It's reasonably priced (the powder is mixed 3:1 with water so it makes more food than you'd think), well hydrated to avoid constipation issues, and has a good ingredient list. It's also fun to feed, and the fish take to it readily in my experience.
I actually go through one of the huge 4.4lb jars every few months around here, so I'm happy to put my own money where my mouth is on this one.
If you decide to try your hand at breeding goldfish and want to get your adults in spawning condition quickly, this is a nice food to have on-hand (I use it for that purpose).
Likewise if you want an easy food to feed to baby fish, this is a solid choice.
The only limitation I'd put on it is that I wouldn't feed much as a "daily staple" to the average fish, since you'll get them quite fat quickly that way.
This product also STINKS when you make it up moreso than any of the others, so don't make up this food just prior to non-fishy friends coming over or around members of the family that aren't understanding about such things.
While most websites devoted to caring for goldfish will tell you to feed as many vegetables as you can stand, I'm going to be one of the few that tell you that you should only do so if you really want to.
In my opinion (and in the opinion of a lot of fellow breeders), vegetables aren't really required to keep healthy goldfish. Yes, even the mighty pea isn't really used regularly by most experienced goldfish keepers.
You see, most people end up feeding goldfish vegetables for one of four reasons:
because someone told them to
because of the evolution argument mentioned above
to give their goldfish something to peck at to be entertained
because their goldfish get "floaty" when fed certain prepared foods
I personally discount #1 without knowing supporting details, have found that #2 is true but doesn't necessarily mean what's normal is what's best, can make a case for #3 but haven't really noticed a benefit, and so end up being left with #4...feeding vegetables to avoid swim bladder problems.
If you've read to this point already you'll already be well armed to avoid swim bladder problems, but the main reason I don't suggest using vegetables in this way is that it's not a good plan to just use vegetable bulk to ram poor quality food through a goldfish's gut (which is what people end up trying to do).
Yes, feeding vegetables like digestive system battering rams works to a degree. Just feeding a better food, smaller meals, or a rotation of foods works just as well however, and avoids a lot of potential water quality issues that might be caused by rotting vegetation or pesticides left on the vegetables.
Even the mighty green pea, touted as the cure to just about everything that ails a goldfish nowadays, has no real magical power. Peas don't even necessarily work better than any other vegetable for the purpose, and are basically popular on the fame of one old veterinary article and for having the advantage of being roughly the right size for most goldfish to eat easily.
As a result, if you choose to use vegetables, use them to compliment or add variety to a healthy diet rather than to compensate for a poor quality dry food. To give you some ideas, check out this fun illustration Erica made to illustrate the benefits of some common vegetables and fruits:
What Goes Into A Good Goldfish Food?
Although many people try to determine the quality of a food from its label (myself included), the real truth is that there's only so much you can tell from an ingredients list. Factors that you can't tell from the outside include:
the quality of an ingredient - nutritional value on the same ingredient can vary widely depending on the quality of a source, without changing the name of the ingredient
the palatability of the food - it doesn't matter if it's the best food in the world if the fish won't eat it
the stability and "mess factor" of the food - whether it will cloud the water, clog your filter, or make your house smell like garlic can dramatically affect how willing you are to feed a food
when the food was packed - except for in a few cases like Hikari, few manufacturers tell you when the food was packed. As we'll see below, that can hugely affect vitamin and nutrition quality
Unfortunately unlike cat and dog food, fish food is completely unregulated in North America. Likewise, while there are regulatory bodies that set nutritional levels for cat and dog food appropriate to different age ranges and developmental stages in their lives ("kitten food" is regulated differently than "adult" or "senior" food), no such research guides levels appropriate for our finned friends.
As a result, the fish food market is very much buyer beware at this point in time - even cost isn't a very good indicator of quality nowadays!
That said, if you're unsure what might be in a food, or if the listed ingredients are incomplete or seem a bit superficial, feel free to reach out to the company directly via phone, email, or social media. The good ones are happy to respond in a reasonable time period, and will be able to provide you with the answers you need.
If a company doesn't respond or gives you an answer that feels like "marketing talk", consider taking your business elsewhere. Modern fish foods tend to be very good in general, so you shouldn't have trouble finding an alternative to one that isn't being cooperative.
What Are the Main Components Of Fish Food?
When looking at goldfish food, the main components of most foods will fall under one of the following categories (not all foods will contain all of the below):
ash (includes minerals)
prebiotics and probiotics
As one of the main building blocks of the body, protein is one of the most important components in building healthy fish (especially young, developing fish).
When looking at protein ingredients, the quality of the protein is more important than anything else. How "bioavailable" the protein is (how much can actually be used by the fish) is particularly important. Both are basically impossible to determine from the label, sadly.
Despite the common understanding of goldfish being primarily herbivores, the protein source that's actually most bioavailable to them is actually fish meal. Made up of the components which are left over after fish are prepared for human consumption, quality fish meal is actually therefore made from "human grade" ingredients and contains all of the essential amino acids (50-60% of the protein component) that a fish needs to grow and develop properly.
On the other hand, mammal proteins tend to be very difficult for fish (particularly goldfish) to digest, and so particularly homemade preparations made from beef heart, meat, offal etc should be largely avoided. The fats from these protein sources are especially non-digestible, and should be trimmed off completely.
For a plant source, the best common protein on the market right now is soybean meal. Although it ideally shouldn't comprise more than 50% of the protein fed to goldfish, it's a nice source of a lot of the same organic components that would otherwise be found from an aquatic source.
"Designer" proteins like soldier fly larvae are also becoming more commonly available, and goldfish keepers are seeing good results from a lot of them. That said, try not to fall for marketing pitches that may be more applicable to humans than to fish. No fish has even been gluten sensitive, for example, and the corn we might avoid as people is actually a cheap and easily digestible protein source that requires only minimal supplementation in fish.
When looking at the protein components of a fish food label, if you start to see a lot of amino acids being listed, start to consider that the proteins that the food is using may not be of very high quality. This is because the addition of amino acids tends to only be required when they're not already present in the food naturally, and the amino acids are trying to compensate for a lower quality, cheaper parent ingredient.
In a general sense, most breeders have found that a good, high quality protein food can really help to develop good eyes, fins and wens in particular (though it's used throughout the body as stated before). Since you'll want to be emphasizing fin carriage and overall skeletal develop before trying to build body mass, make sure that young fish in particular have access to abundant, high quality, and highly bioavailable protein sources.
While the protein levels needed by fish in general are said to make up 25-55% of the food taken in, our omnivorous goldfish tend to need a little less protein than their carnivorous cousins. As a result, a protein makeup of 35-45% is usually most appropriate, with less active breeds needing less protein in general.
A Quick Note About "Crude" Ingredients
Sometimes an ingredient will be labelled as "crude" on a listing; particularly as a protein source.
Although this conjures up terrible images of crude oil lacing a pristine beach somewhere, "crude" in this context corresponds to the method that the lab uses to analyze the food, and not to any statement of quality of the ingredient itself.
As a result, don't be scared off by the word crude on an ingredient label.
Although a lot of people tend to have negative connotations surrounding fat, it's actually quite a critical source of hormone production, energy, and insulation for our goldfish friends.
Feeding an extreme amount of fat to a fish has the same obesity-related issues it does with any animal, but kept to a sensible 10-25% of diet it will provide all the building blocks the goldfish needs to be happy and healthy.
If you keep an eye on condition and learn the difference between normal and obese for your breed, you'll be able to learn what the right level is for your particular fish. If it gets to the point of having trouble swimming in particular, you'll want to back off a bit.
Fish in general have a need for large amounts of N-3 fatty acids, and since these are not usually found in vegetable sources, this is another argument for animal/fish based foods.
Carbohydrates are the primary energy source for your fish, but can at times be poorly digested and excessively high levels can affect liver function (since insulin effects work differently in fish than they do in people).
As a result, try to look for a carbohydrate level between 25-40% for a goldfish food, but not too far beyond that level.
That said, good quality carbohydrates will help to build bulk in the body of your fish, and attention paid to good carbohydrate containing foods can really help to finish a fish that's otherwise well developed in its finnage and overall form.
Ash (Mineral Content)
Another ominous sounding ingredient, ash is a component that most people seem to think indicates a poor quality food if found in large amounts.
While this may be true in some rare cases, ash is actually primarily the mineral content of the food, and is labelled as ash because it's what's left over after the lab burns off the other more complex components during nutrition testing. It can also contain things like bone and other non-combustible products.
There isn't a recommended "level" of ash in a goldfish food per say, and so you have to learn to look at little deeper into what's making up that ash content.
In general, people with at least moderate levels of General Hardness (GH, >3 dGH via test kit) and Carbonate Hardness (KH, >3 dKH by test kit) should have minimal need to supplement minerals to their fish with the exception of phosphorous.
Phosphorous is generally not available easily from most water sources, so finding a food with a phosphorous content of 0.3% (or adding a mineral supplement to do so) is a good idea.
As a kissing cousin to mineral content, vitamin content is especially important for the health of your goldfish.
Coming in both water-soluble and fat-soluble forms, vitamins A,C,D,E and K are the usual suspects to consider when evaluating the vitamin content of a food you're considering.
Vitamin A is a largely a skeletal structure influencer, and is especially important for young, developing fish.
Vitamin C and E can be largely considered prebiotics in fish, in that they can be a component of enhanced immune response. Vitamin C in particular can be fed in very high doses to great effect.
Vitamin D function in fish in still not well known or understood, but especially for indoor fish that are not exposed to sunlight, fish are almost wholly dependent on dietary sources of vitamin D and store great quantities in their tissues if allowed to do so.
Vitamin K function in fish is especially critical given that it plays extremely crucial roles roles in blood coagulation and bone mineralization.
It's worth noting at this point that even if the food you're considering has the vitamins that you know it needs, most vitamins are very sensitive to temperature changes, light and moisture. As a result, how the product is handled and stored plays a large role in whether it will work out well for your fish.
Vitamin C in particular is very unstable, and foods can start to see a loss of vitamin content 90 days after packaging if the food uses stabilized vitamin C sources, or after 30 days if it uses a non-stabilized version. In a nutshell, if you've ever wondered why Hikari uses peculiar foil-based packaging, this is largely why (and this is also an argument against buying cheap, old-stock fish food).
Likewise, if you've ever wanted a reason not to store your fish food for too long, or to skip to cheap bulk container that you'll take a year to feed out, promoting healthy vitamin content is a good one.
As an option for both good and old foods, supplemental vitamins are available in most good stores. I personally use these products to stay on the safe side with our homemade foods, since I don't have the resources of a lab to know exactly what's in each of my ingredients. A great option is Vitachem, which comes in a convenient liquid form:
Although goldfish keepers online seem obsessed with feeding huge amounts of bulk fibre to their fish, there isn't a particularly good nutritional argument for doing so.
Avoiding constipation in our fish is a good thing to avoid problems with bloat and dropsy, but as has been stated earlier in this article, there are better ways to do this than to try to force low quality food through the fish with bulk fibre.
Feeding too much fibre even runs the risk of pushing food through the digestive tract too quickly, before the fish has the chance to properly digest it.
As a result, there isn't really a recommended level for fish food fibre that can be based on a nutritional reason.
Different foods will have different moisture levels, and the only real comment that can be made on moisture from a nutritional perspective is that it will influence the percentage breakdown of ingredients shown on the label.
Some keepers will try to hydrate their foods prior to feeding them to their fish in order to try to avoid bloat issues, but this has the downside of causing premature loss of water soluble vitamins.
High quality foods fed in appropriate portions should not cause bloat in goldfish, even if used without presoaking.
In general, color enhancers are misunderstood and misused by the average goldfish keeper.
First off, when looking at an ingredient list it's important to understand that color enhancers can come in a number of forms. They can be natural sources like krill and shrimp (containing astaxanthin), natural algaes, yeasts or bacteria, or even synthetic minerals or pigments.
As a first example, the primary source of color enhancement for orange (itself a mixture of red and yellow) tends to be one form or another of a betacarotene molecule. This can be found in terrestrial sources like carrots (exceptional fans of carrots sometimes ending up with an orange tint to their skin) or aquatic sources like seaweeds or spirulina algae.
If you are instead looking to enhance red you might turn to a betacyanin containing food like beets, or a marine product containing astaxanthin.
For a canary yellow, a food containing betaxanthin would be an option (those often having a plant source). Lutein is also found in egg yolk, which is an easy ingredient to add into a feeding regimen.
Those different sources can have different impacts on particular colours in goldfish, so it's important to understand what you need and what the effects of various color enhancers might be on your particular fish. As good as the thought of enhancing the color of your fish may be, doing so via food isn't something that should be done lightly for a number of reasons.
First off, when you use a color enhancer that targets a particular color, you should be aware that they will apply that tint to all the scales the fish possesses, regardless of color. This is why owners of multi-colored fish with a white base often complain of certain color enhancing foods "yellowing" out the white areas of their fish, and why Hikari uses a claim that theirs don't cause yellowing as a large part of their promotional literature.
Possible issues you might encounter would be examples like the following:
feeding a red and white fish carotene will cause the red will take on some yellow, turning the red more orange and the white slightly yellowish
adding betacyanin to a red and white fish might result in a dark red fish with a pinkish tinge to the white areas
adding almost any color enhancer to a purple or blue base will make the fish look very different, since it will tend to blur or dull out the native black colours
Even used appropriately, a fish can't really be taken to extremes using foods alone. Likewise, feeding the food year 'round doesn't have any markedly better effect than feeding it for short periods, and given the cost involved doing so only as a preparation before a show may be a better use of funds.
So as with anything, having a bit of extra knowledge to arm yourself with here can make sure that you don't end up causing a problem rather than getting a benefit from the extra dollars spent on color enhancing foods.
As a final word of warning, beware of sellers which feed their fish color enhancing foods. If you don't feed the same foods, the vibrant colours your fish arrives with may not stay for the long run (sunlight exposure can act similarly). A responsible seller should be willing to tell you what they're feeding with no hesitation.
Prebiotics and Probiotics
Broadly speaking, both prebiotics and probiotics are good for goldfish if supplemented in quality food.
Likewise, given the cost of adding them, the presence of these products in food is a good sign that the rest of the food is likely to be of at least reasonable quality.
Probiotics are bacteria added to feed to aid the digestive processes of fish. Since they must be able to tolerate bile and stomach acids, only particular strains of bacteria are suitable for this task. Examples you might see on labels include lactic acid bacteria l.lactis, l.plantarium, and l.fermentum.
Prebiotics instead are aimed at supporting and enhancing the fish's natural immune system. Examples of common prebiotics include garlic, beta glucans, and Vitamin C (ideally in a stabilized form).
Medicated foods are an area that you should approach with caution, since there is absolutely no control of what medications can be added to fish food.
One source that I can recommend without hesitation is to approach a knowledgeable aquatic vet to purchase proper medicated products. Since those are primarily only available via prescription they'll be targeted appropriately, stored appropriately, and properly active upon delivery.
When using a medicated food, ideally each fish to be dosed should be housed in its own dedicated hospital tank. This can seem like a hassle, but it's the only way to be sure that one fish isn't getting dramatically more of a medication than another. Especially given that sick fish tend to not have much of an appetite and may take a while to finish a block of food, having a competition-free environment is a really good idea.
Those wanting to find an aquatic vet should visit Fishvets.org or Aquavetmed.info to find help, though those of us in the landlocked portions of the world may find these professionals a little hard to come by (ours is a 4 hour drive away).
Slightly less reliably, you can add certain medications like internal dewormers to gel foods like Repashy or homemade foods like steamed egg. If you chose to do so, be sure that you don't add them when the food temperatures are high enough to affect the medication (this will vary by medication). I've used Metroplex and Kanaplex to good effect in this way with my fish.
Feeding dewormers in food gets them where they need to be in order to be the most effective.
In order to help the medicine be more effective, products like Seachem Focus can be added to help bind the medication to your food. These products also help to more even distribute the medication throughout the food, making sure that each bite is more likely to contain an effective dose of medicine.
Seachem Focus helps bind the medication throughout your food mix
If your fish is reluctant to eat the resulting mix, Seachem Garlic Guard adds a garlic enhancement to your food which is known to be an appetite stimulant. Particularly useful for fish which are either picky or not feeling well enough to eat, this is quite a useful product to have in your medicine cabinet.
Even further down the reliability chain would be a commercial medicated food (usually flake) that's sold via one of the normal online vendors, but one which at least lists the active ingredient or medicine contained within the food.
Without knowing how old the food is or how it's been handled and stored, this type of food can still have dubious medical value if the active ingredient has been damaged in transit.
Last and most ridiculous are foods which are sold as "medicated" but which don't even list the medical ingredient. You'd have to be borderline reckless to feed something like that, since it's nothing but a marketing sales pitch at that point that you have no way of checking on.
My favorite offender on that front is the Kenta brand of medicated food, which is sold under the tag line “Prevention...is better than to have to cure” (note the lovely grammar contained therein).
Here's the sales pitch:
"Introducing 'Kenta' A medicated food for Goldfish.. this revolutionary goldfish food is created by a veterinarian who treats goldfish on a daily basis. The medication added to Kenta is being used in fish hospitals, so it’s a high grade medication that is effective."
I think the only thing that can be usefully said is that "if it seems to good to be true, it probably is". More practically, feeding anything that has an actual active medication without needing to do so (or without even knowing what you're feeding) is how we end up with overuse problems leading to antibiotic resistance in particular.
Although the sales pitch sounds good and authoritative, no responsible vet I know of would prescribe medication without a reason, and none would use them just for giggles "on a daily basis".
In a nutshell, if the company won't tell you what's in the product (and Kenta won't, claiming they don't want to be copied), I'd personally keep such things far, far away from my fish.
Storing Fish Food Properly
Now that you've learned all about what goes into a good goldfish food and you've decided on the one you want to buy, how should you store it properly? Given that most people tend to store the can of fish food container near the fish for convenience without even thinking about it, most people don't even consider this question.
When you think about what goes into fish food, however, you'll quickly realize that the best way to treat fish food is just like how we treat human food: store it in the fridge, and don't feed it for too long.
Cory from Aquarium Coop has a good analogy for this. Think about a bag of potato chips. Opened on the first day, they're fresh and tasty. Even a day or two later, they still likely to taste just fine. When it starts to push a week or more, however, things are likely to be getting a bit stale and chewy (and the odds that you'll end up with a stomach ache get higher quite quickly).
The argument for proper storage gets even stronger in the case of fish food given that it tends to contain fish oils and vitamins if formulated properly.
Even stabilized, fish oils will eventually go rancid in the same way that fish left out of the refrigerator will. If you one day notice that your fish aren't eating as well as they normally do, check the expiration date of the food. Simply buying a new can of food might return them to their eager, begging ways.
More seriously, if your fish are experiencing health problems that you can't explain with water quality or parasitic disease, checking on the expiry date on the fish food can is often a good first step in restoring them to health (consider marking the date you opened the can on the side with a marker as well).
From a nutrient perspective, as discussed earlier after 90 days most vitamins are starting to lose their potency. Feeding "old" vitamins won't tend to create issues like spoiled protein or fat will, but the fish won't be getting the benefits that they'd otherwise be getting from fresh ingredients and in extreme cases may start to show the effects of nutrient and vitamin deficiency.
In the end, if you can get your family to be understanding enough to look the other way when a can or two of fish food gets stored next to the salad dressing, that's ideally the best way to do things. Worst case, a small bar fridge is usually available from Craigslist or Kijiji fairly inexpensively.
Buying Bulk vs Small Portions
Although at this point you can probably guess what I'm going to say here, I'd strongly recommend that you only buy as much food as you can safely feed out in about 90 days.
Yes, the larger container usually result in a lower cost per volume. Making sure you feed it out before it spoils can be a challenge, however, and if you feed spoiled food you can end up with health care costs far greater than what the couple of extra dollars spent on a new can of food might bring.
One option for those that still want to go the bulk route is to take the larger food container, vacuum pack smaller portions right when first opened, and to open these smaller portions as they get used up.
If you don't have easy access to one of the above, here are some alternatives that also feed out well. Luckily, we're a bit spoiled for choice with modern foods, and it's honestly hard to go too far wrong:
Hi there, we're Adam and Erica Till, and we're the owners here at Arctic Lights Aquatics. We're goldfish breeders in Canada, and our mission is to provide you with everything you need take care of your goldfish.
After figuring out the best food to feed your goldfish, you next questions are likely to be how much and how often should you feed them. I take the guesswork out these questions for you, and the answers might surprise you!
Have you ever wanted to reduce your feed bill, find a nutritious food that's customizable to different stages of your fish's life, AND have a bit of fun in the kitchen? No? Oh. Well, this is a great food anyway!
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