Goldfish Diseases: An Interactive Guide To Figuring Out Why Your Goldfish Is Sick and How To Cure It

by Adam Till

A Note Of Warning About Goldfish Disease and The World "Wild" Web

First off, I'm very sorry that you're having trouble with your goldfish.

There is an awful lot of conflicting information on the web, and most if it is because of websites repeating information from other websites without having direct experience with treating disease themselves. Usually this is best recognized by the lack of original photographs of the disease processes, and a lack of references to claims made in the article or treatments suggested.

Please be careful treating your fish using such information, and always contact an aquatic veterinarian for assistance whenever possible.

Since I am just a breeder and not a vet I cannot legally diagnose or prescribe a course of treatment for your fish, so instead I will simply offer a description of what I do when I encounter these issues.


Short Take

Let our little goldfish paste give you a quick intro...

There are few things that are more frustrating and scary in goldfish keeping than having to care for a sick fish. 

Likewise, when you do have a sick friend there are few things more frustrating than having to wade through a huge list of disease possibilities on multiple websites or in books with no easy means of narrowing them down.

To that end, I developed this page to be an interactive guide that allows you to quickly eliminate  possible diseases based on selecting symptoms that your goldfish is showing.

If you click on a symptom, diseases which aren't commonly associated with that symptom will be removed from the page. When you scroll down below the symptoms to the disease list, a short summary of possibilities is available under the heading Diseases Which Match Your Selected Symptoms.

As you click off additional symptoms that you're observing, the list will narrow more and more. Try not to choose too many symptoms at once or you may end up with nothing left in the list.

Eventually, you'll hopefully end up with a short list of possible diseases that your fish may be suffering from. It won't replace proper medical advice, but it'll at least be better than staring at a list of 50-odd diseases in overwhelmed horror not knowing where to start.

Once You Think You Might Know The Problem With Your Fish...

In each case, I've tried to list one or more possibilities for ways that myself and other keepers and breeders of goldfish have dealt with some of these issues.

It unfortunately won't guarantee that you'll be able to get hold of some of these options based off where you live, but I do my best to provide a variety of possibilities and to remove options which fall out of production.

You should ideally never treat anything without knowing exactly what you're dealing with (later on I'll talk about learning to use a microscope, for example), but when faced with a sick fish and limited options, I understand the feelings involved and encourage you to do your best.

For now though, let's get on with narrowing down your list of possible problems.

Quick Navigation

Symptoms

 

Diseases

Please note that although I'm adding disease descriptions all the time, that does take time. If you don't see what you're looking for right away, feel free to join me and other breeders in The Goldfish Council's Facebook group, which is one of the few other places on the web where you can find reliable information you can trust.

Diseases Which Match Your Selected Symptoms

Acidosis

Symptoms:

  • gasping - due to decreased gill function, fish may struggle to get enough oxygen from the water
  • darting, hyperactivity or attempts at jumping - in an attempt to leave a body of water that is literally burning them, fish that are still strong may react violently to the damage being done to them
  • lethargy - for fish that are more sick, they may not have the energy to move very much
  • excessive slime coat production - in an attempt to protect its skin and gills, the fish will react by producing much more slime coat than normal
  • dark red gills, visible gill damage, and browing of the area around the gills- damage to the gills from acidic water will result in visible gill changes

Description:

Caused by water which has been allowed to drop too far in pH, acidosis occurs when the pH has dropped below 5.5. This is normally not possible using injected CO2 alone as with a planted tank, and is will generally only occur when decaying waste buildup drops the pH in water with low carbonates (KH).

Although fish don't tolerate large changes in pH well at the best of times, this can be especially dangerous when those changes occur quickly.

Goldfish are not tolerant of extremely low pH for extended periods of time, and the usual result of this is extreme damage to gill and skin tissue.

Low pH also starves and eventually kills off the filter bacteria in your aquarium, which can make recovery of the fish difficult even if the condition is noticed in time.

Fish with acid damaged gills are particularly sensitive to oxygen issues, and will frequently be seen gasping at the surface (particularly in the morning or at night as plants or algae help use up dissolved oxygen). Left uncorrected, fish will start to die (largest first).

Prognosis:

Guarded.

Acidosis can cause massive gill damage and a greatly suppressed immune system.

Combined with damage to or destruction of the filter bacteria colony, this can setup a condition where the fish is extremely vulnerable to infection.

Treatment:

The first step in determining if an acidotic condition exists is to run a low-range pH test.

API Master Test Kit (Includes pH)
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At all times of the day (check first thing in the morning in particular), the water pH should ideally be above 7 and at least 6.5.

The next step is to start to raise the pH of the water using small, frequent water changes (twice daily 10% or similar). This will raise the pH slowly to avoid shocking the fish, and avoid large swings in temperature.

Next, in order to avoid the issue in the future, maintenance on the tank or pond should be stepped up so more of the decaying food, waste, and plant matter is removed on a regular basis.

Consider purchasing a gravel vacuum or using one more frequently, removing debris from about 25% of the tank surface each weekly water change.

Python Gravel Vacuum
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Ensuring that waste doesn't build up is one reason a lot of goldfish keepers like to run gravel-free tanks. One possible hybrid model is a partially bare-bottom tank, where food is only fed on the bare sections to avoid food loss.

Another important way of avoiding this issue is to ensure that at least 3dKH (measured using a KH test kit) is maintained at all times:

API KH/GH Test Kit
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This can be done using baking soda at each water change, but is best done using crushed coral added to the substrate. Baking soda can change KH (and therefore pH) very quickly and can be dangerous if used improperly, so most people prefer the slower-release coral option. Goldfish keepers with soft water have to work harder to keep pH in the right ranges.

Once the basic setup is corrected, remember that if the filter bacteria are killed off you'll have to cycle the tank from scratch again. Water parameters will have to be monitored for ammonia and nitrite quite closely, and water changes performed to keep these levels to 0.25ppm or less.

Moreso than new, healthy fish, acidotic fish will be very vulnerable to ammonia and nitrite damage. Particularly if exposed to high levels of nitrite, this will be what causes the gill tissue and area to turn a dark shade of brown.

Since oxygen availability is very important with fish that have gill damage, be sure to have an air stone or air-powered filter running at all times. Do not be tempted to turn these off at night to make the tank quieter, since that's when they're most needed.

Never Clog Air Stone
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Lastly, if the tank is stocked heavily and this was contributing to building up waste too quickly, consider rehoming some fish to another tank. If stocking density is greater than 1 fish per every 15-20 gallons, most people struggle to keep water quality at an acceptable level.

Aeromonas / Furunculosis

Symptoms:

  • loose feces (poop), diarrhea, or slimy white feces - internal aeromonas infections can mimic gut parasites, but will not respond to deworming in the same way
  • swollen body, dropsy - stress from an infection may cause swelling of the gut up to and including full-blown dropsy
  • floating, sinking - aeromonas infections of the swim bladder may be caused or aggravated by ammonia spikes or similar
  • red sores, red streaks - infections of the tissue may progress to eating away at tissue, and infections of the blood stream will be visible if severe
  • bulging eyes - "pop eye" (where the eyes protrude unnaturally) is often caused by aeromonas bacteria
  • fins dissolving - damage to fins may be a result of aeromonas infection

Description:

Aeromonas infections are relatively common with goldfish and other tropical fish, and are caused by one of a number of opportunistic gram-negative bacteria.

Although these bacteria are found in most environments, they do not normally cause issues for healthy fish. When aquarium conditions deteriorate, or the fish become stressed by poor nutrition, overcrowding, perceived danger, or other health issues, aeromonas bacteria colonies may flare up to the point of becoming problematic. Most fish can deal with one or two stress factors, but when stressors accumulate then problems can arise.

It should be noted that gut infections of aeromonas can often mimic the symptoms of some parasitic diseases, which can frustrate owners who assume they should be using a deworming medication. Should that be the case, dewormers will not likely be effective against the actual bacterial problem.

Please be aware that you the owner can potentially become infected with aeromonas bacteria if you handle fish or mucous from infected fish and have open cuts or wounds. Take care in handling such fish if you have breaks in your skin at the time.

Prognosis:

Moderate to poor, depending on water quality and aquarium maintenance.

If the disease has progressed to open body sores or advanced, widespread septicemia (extensive red streaking), most severely sick fish will struggle to recover.

Likewise, if sanitary conditions as discussed in the following section are not corrected and maintained, then no treatment in the world is likely to help for very long.

Treatment:

Aeronomas and pseudomonas (both gram negative bacteria) are some of the leading causes of pop eye (bulging eyes). To avoid duplicating that information, please see the section on this page pertaining to pop eye if that is present.

Likewise, if dropsy is present, there is an extensive article on treating dropsy available here.

Swim bladder disorders (causing floating or sinking issues) are also a distinct possibility, and are covered on this page in the section on swim bladder disease.

If poor sanitary or water conditions in your aquarium have contributed to the start of an aeromonas infection, no medication in the world will be effective in the long run. As a result, perform the following checks before starting any treatment program:

  • water parameters test at 0 ammonia, 0 nitrite, <40 ppm nitrate
  • for goldfish in particular, check that your pH is always above 7 and that it doesn't change very much over the course of a day (which will require a KH of at least 3 dKH on average, covered later in this section). Low pH will tend to aggravate aeromonas infections
  • check to make sure your filters are clean, and are working properly
  • if you do not currently run an air stone or some form of filtration that heavily aerates the water, consider adding one (aeromonas thrives in low oxygen situations)
  • check to see that there is adequate circulation in all areas of the tank, which allows circulation of oxygenated water to those areas. Changing the placement of filters or adding circulation pumps can help remove "dead spots" of low flow
  • make sure that you haven't let excessive amounts of waste build up in the tank, and if you've been putting off mulm vacuuming, do so now (this may result in cloudy water if you do a lot at once as filter bacterial populations rebalance; this is generally harmless if unattractive)
  • if you live in a very soft water area, consider adding something like a Wondershell to allow for proper mineralization of the water and to bump KH (carbonate hardness - can help the fish better regulate internal chemistry by not having to work their kidneys as hard):
    Wondershell
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In cases of very mild aeromonas infections, use of both Melafix and Pimafix combined may be tried to halt the progression. These are not typically particularly effective, but are commonly available at even most local chain stores.

API Melafix
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API Pimafix
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If your tank (or pond) is maintained at temperatures below 65°F, you may be dealing with aeromonas salmonicida (which is also known as furunculosis). Treatment of those sorts of tanks is more difficult since many medications are less effective at lower temperatures. Ideally consider raising the temperature above 65°F at least for treatment of infected fish if possible.

If your pH is above 8, Triple Sulfa and Kanamycin are good choices for gram negative bacteria like aeromonas:

Kanaplex (Kanamycin)
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SulphaPlex (Triple Sulpha)
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Kanamycin becomes particularly effective when combined with nitrofurazone, as a note.

Nitrofurazone
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Tetracycline products including Maracyn 2 and Doxycyline are targeted to the right bacteria, but have the side effect of lowering red blood cell count (which may be hard on infected fish with open wounds):

Maracyn 2
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Doxycyline is harder for most people to find, but particularly for low temp applications, can be useful (especially when fed food soaked with the medication).

If a natural remedy is desired and Melafix/Pimafix is not effective, KoiZyme may be an option:

KoiZyme
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This product does not attack the bacteria directly, but competes with it for nutrients and can help the fish fight off infection indirectly.

If fish are suffering from fin rot that's secondary to an aeromonas infection, Maracyn One may be particularly effective.

The trimethoprim component of Maracyn One can lower blood platelet counts, however, so should be avoided if fish have open wounds which need clotting (need to stop bleeding). Use of this medication with such fish will usually be fatal.

If open wounds are present, swabbing the fish with merbromin can help (AAP Aquarium Wound Control).

Baths in double-strength methylene blue are also an option in this situation (though this should be done outside of the main tank to avoid cosmetic damage to tank seams):

Fritz Methylene Blue
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As a compliment to (not replacement of) medication, aquarium salt can be added at 1 tablespoon per 5 gallons:

Bulk Aquarium Salt
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This will not replace more direct treatment, but can help speed healing of sick fish.

To help kill off aeromonas bacterial colonies in the water, use of a UV sterilizer will go a long way in minimizing further infections of fish in the future.

Since as was said earlier that aeromonas infections thrive in low oxygen water, if you are concerned that you might be in that category consider picking up a dissolved oxygen test kit:

Salifert Dissolved Oxygen Test Kit
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Ideally you'll see a reading of at least 5-7ppm when using that kit. Use of air stones or other similar simple devices will go a long way to fix this potential issue, as long as they are used in a tank with good overall circulation/flow.

Alkalosis

Symptoms:

  • open wounds, red streaks, white skin - chemical damage to the fish's skin will become obvious in varying ways depending on the color of the fish
  • fin shredding - if allowed to build up over time, fin damage may become apparent
  • darting - in order to escape conditions which are hurting it, the fish may attempt to leave the tank in any way possible
  • dark red gills, gasping - damage to the skin will usually mean damage has been done to the gills as well, making the fish struggle to breathe properly
  • dying - since fish can only adjust to changes within a certain range, some may not be able to adapt quickly enough

Description:

Alkalosis is stress that comes as a result of having the pH in your aquarium rise too high to be safe to keep goldfish.

Before this condition can be blamed for damage to your fish, however, you have to understand that this tends to happen at a pH FAR greater than the "7.0-7.6" continually quoted by a number of goldfish websites. A large number of breeders (ourselves included) produce huge numbers of healthy fish with water in the 8.0-8.4 range, and most of the continental North American population that doesn't live right on the coasts will have water that looks much like this. Goldfish actually thrive in moderately hard, alkaline water.

If your pH rises into the mid 9's or higher, however (out of the range of most hobby test kits), there's a case to be made for considering alkalosis as an issue. Studies have found about a 10% loss or so after 24 hours with goldfish fry (generally the most fragile life stage) starting at about a pH of 9.5.

In more moderate pH ranges (say, 7.8-8.8) the problem that most people end up facing is actually ammonia toxicity. After all, far more so than down at around neutral pH (7.0), ammonia is extremely toxic for fish at high pH ranges.

As a result, when a fish starts to struggle at high pH, it's often suffering from ammonia poisoning rather than dealing with anything to do with pH.

In order to remedy ammonia issues, your filters should be cleaned and you should become very familiar with the process of properly cycling an aquarium. The common excuse of not having a test kit is really not acceptable for anyone who hopes to keep fish successfully, so please pick up an inexpensive test kit and learn to use it to keep water in healthy ranges (it's a necessity, not a luxury, and generally less than the cost of a single good goldfish).

API Freshwater Master Test Kit
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If you discover ammonia problems, please navigate to the section on ammonia poisoning and follow the instructions you'll find there. At the very minimum, cleaning up the water and avoiding using any medications if your fish's gills are extremely dark red is important. That redness indicates gill damage, and given most medications extract oxygen from the water in the action, it can be extremely risky to medicate fish with inflamed gills.

For cases of true alkalosis, first begin by comparing your tank or pond water to a sample taken straight from the water source (aerate both strongly with air stones to get most accurate results).

If your source pH is well over 9, there's a case to be made for cutting it with reverse osmosis or bottled water, or finding the few fish like African cichlids which will thrive at extremely high pH levels.

More often, very high pH levels will occur for one of the following reasons:

  • when tanks have been continually topped off for evaporation with water rather than being changed properly (minerals don't evaporate and therefore build up)
  • inappropriate rocks or gravel have been used to setup a tank
  • new concrete-lined ponds have not been acid treated or sealed
  • when chemicals are added by the local water department during upset conditions in their water treatment plants

In the first case, the problem can usually be eliminated by a series of water changes to flush out the accumulated minerals. Water changes should always remove some of the old water to avoid this, or top off water should be reverse osmosis or distilled water (neither of which contain mineral content to build up and cause problems).

If rocks or gravel are the culprit, you'll often find that the pH will steadily increase over time. Some people try to use a drop of vinegar on the rocks to see if an acid "fizz" is noticed, but the true test is to immerse them in a bucket of water and test to see what the pH does over about a week or so. Most people change enough water in a goldfish tank that this doesn't really become a problem even with carbonate-containing rocks, but it's worth checking nonetheless.

If concrete is to blame, understand that newly constructed ponds should always be acid washed or sealed to prevent leaching of carbonates into the water. Without this, high levels of lime can make a noticeable change in the pH; ultimately killing any animals added to the pond. People with acidic water sources will be particularly prone to issues here.

The final instance (additions of chemicals to the water by city water departments) is the hardest to combat, and can be the most frustrating. Since the city is only responsible to provide safe water for drinking (and to keep their pipes safe), many aquarists have lost fish over the years as the water chemistry is altered dramatically. This is particularly common during spring runoff or during plant maintenance as systems become overloaded.

About the only thing you can do to avoid falling victim to this is to check your water source before doing your water changes. Huge increases in chlorine, chloramine, ammonia, nitrate or pH or drops in dissolved oxygen have all caused fish losses over the years, and all are testable with the appropriate liquid kits or strips. This is why some people insist that water be "aged" before being used for water changes, but that's definitely on the extreme of what most of us can manage (or are willing to do).

Some cities offer email or text services you can subscribe to in order to be notified about such events, but even if those don't work, don't expect much sympathy or compensation for fish losses as a result of water changes made to city supplies. After all, they're only responsible for things that affect human health and safety.

    Prognosis:

    Variable - it depends on how far the pH has been altered from what the fish were used to or raised in.

      Treatment:

      If the actual problem is ammonia poisoning, the water must be slowly changed out with clean water to remove the ammonia source. Do not do this all at once or you may shock the fish to death with clean water. Most fish will tolerate 20-30% changes every few hours until the conditions are restored, but check with a vet or use your best judgement.

      When the ammonia is first noticed, products like Prime can be added to temporarily (~48 hours) detoxify ammonia:

      Seachem Prime
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      This will buy enough time to gently remove the ammonia.

      If dark red gills are noticed (indicating gill damage) and the fish seems to be struggling to breathe, a therapeutic dose of aquarium salt at about 1 teaspoon per gallon may ease breathing difficulties.

      Bulk Aquarium Salt
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      If the problem is pH shock or extremely high pH ranges, the fish should be immediately removed and added into a body of water that's about 0.5 pH units lower than the contaminated water. After this, the water should be gradually diluted down to a safe level in much the same process as you'd use to correct ammonia in the water.

      Again, err on the side of slower transitions rather than quicker ones, and try to match temperatures at all times.

      Ammonia Poisoning

      Symptoms:

      • clamped fins, bottom sitting, lack of energy, no appetite - high levels of ammonia in the water are very hard on fish, and will really sap their energy level
      • gasping at the surface - ammonia will damage the gills of fish, causing them to struggle to find enough oxygen
      • turning pale, increased slime coat production - ammonia in the water will damage the skin over time, leading to irritation and discoloration
      • black spots, black fin edges, patchy damaged-looking color changes - black marks will indicate that there was potentially some damage done to the fish at some point, and that it's now healing. Potentially an indication of previous rather than existing problems
      • red sores on body, red blood streaks in fins - fish suffering from ammonia poisoning will be prone to developing septecemia and other infections, often showing up in the fins first. High ammonia levels in shipping from sealed bags will often result in blood streaking in the fins
      • fins dissolving - long term high ammonia levels will often cause fin damage that becomes obvious as the fish gets weaker

      Description:

      Ammonia is a normal waste product produced by fish, and is released by their gills and excretory systems as part of normal body function.

      Although very toxic in even small concentrations, in the wild that ammonia rapidly disperses by the huge water bodies most fish live in. Once there, the ammonia is consumed by plants and algae and used for fuel for plant growth.

      In a home aquarium, getting rid of ammonia is the job of a properly setup and cycled aquarium filter. In fact, the common term "new tank syndrome" is really just a strange way of describing a tank that doesn't have a mature filter and is killing its fish through ammonia (and possibly nitrite) buildup. Goldfish or betta bowls without filters are really just fish stewing in ammonia.

      In fact, it would be easy to argue that ammonia poisoning does more damage to or kills more fish today than disease, poor feeding, or just about any other harmful element.

      When it comes to detecting ammonia, a good test kit is your best friend:

      API Freshwater Master Test Kit
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      Although ammonia is colourless and therefore hard for new fishkeepers to notice, experienced aquarists will often be able to smell ammonia issues with little problem. My brief attempt to keep bettas in traditional, unfiltered jars ended on day two when I went to change out the ammonia-soured water in the jars (it just SMELLED unhealthy).

      Exactly how toxic ammonia is at any given point will depend on the pH that your tanks normally operate at.

      Below a pH of about 6.4 ammonia actually converts to far less toxic ammonium, and can be treated much like nitrate is at higher pH levels (a little is okay, a lot is harmful). Relatively few aquarium fish will be happy down at those pH levels (goldfish will be especially stressed), but it's worth knowing about if you plan on keeping acid water tanks.

      At normal pH levels of 6.8-7.4 ammonia becomes very toxic, and at the extremely high pH levels of 8+ that most of us in hard water areas deal with ammonia is correspondingly extremely toxic. Ideally ammonia should never measure more than about 0.25ppm on a test kit even when your aquarium is cycling with fish in it, and water changes are the order of the day if you see levels above this.

      Although generally not a problem for most goldfish tanks, higher temperatures will also influence how much ammonia will be present in toxic forms. For breeding or fry tanks kept at higher temperatures, be especially careful to make sure ammonia levels are not observable.

      Logically enough, the more fish the aquarium contains, the faster ammonia levels will rise. Especially if those levels exceed what your filter can convert at any given time, this is largely how overstocked tanks end up in trouble.

      Although the usual source of ammonia is from the fish in your tank themselves, it's also worth mentioning that ammonia is produced by a number of other sources in your tank. Those can include leftover food breaking down that isn't eaten, dead plants and animals that are hidden in the corner and rotting, and even poop and other waste that doesn't get taken care of through healthy biological processes. Proper tank mainteance will help to avoid these sources becoming a problem.

      Most confusingly for new fishkeepers, ammonia and other waste products can sometimes be present in the tap water you use to do your water changes. If you've been trying for months to control ammonia levels and you can't figure out where they're coming from, it's worth testing your tap water directly to see if a complaint to the water department is in order.

      In a healthy tank, no measurable ammonia levels should be present. Nitrosomonas bacteria in your filter should convert any ammonia into nitrite (and eventually others to nitrate), or plants/algae in your aquarium should consume the ammonia directly.

      Prognosis:

      As with most issues, how sick the fish becomes is a matter of how quickly the ammonia is noticed.

      Small amounts of ammonia (0.25 ppm or lower) are tolerated by all but the most finicky fish (0.6 ppm is usually the threshold where some start to die), but higher levels will become almost instantly toxic.

      Since pH affects how much of what you measure on an ammonia test kit is toxic (the kits measure Total Ammonia Nitrogen or TAN, which is the combination of ammonia and ammonium), it's especially important to stay on top of things if your pH is on the high side (8.0+).

      Fish removed to cleaner water (or who live in tanks where the water is changed out as soon as ammonia issues are noticed) may survive and recover, but if symptoms are advanced, it may be too late.

      Once you understand that "new tank syndrome" is really ammonia poisoning, never let it be an excuse for killing your fish through a lack of water testing.

      Treatment:

      To determine how dangerous the ammonia in your aquarium is at any given time, be sure to have a good ammonia test kit on hand (the link above is a good option).

      Just remember that your pH will have a large effect on how toxic that ammonia is, and deal with ammonia before making any adjustments to pH. Ideally you want a pH of 7.0 or higher for best filter function, but remove any ammonia/ammonium before adding crushed coral or baking soda to raise your pH to 7.0 (or higher).

      The best treatment for ammonia poisoning, unsurprisingly, is to remove the ammonia that is poisoning the fish. Try not to do so too quickly with huge water changes however, or you risk shocking the fish by changing the conditions too quickly (especially if the pH has dropped substantially lower than the water you'll use for changes).

      If only small amount of ammonia are noticed, then one or two large water changes of 50% or more should clean the problem up (assuming that this sort of large water change is normal for you).

      If your fish are more used to small water changes (30% or less weekly), or the ammonia levels you measure are extremely high (2ppm or larger), than small changes of about 20-30% every few hours should be done until safer levels of 0.25ppm or less are reached. Emergency large water changes are still a possibility, but hold the risk of shocking the fish (this needs to be balanced against the potential risk of the polluted water).

      For fish with breathing difficulties, avoid even mild medications like Melafix or the like altogether since most medications affect the amount of dissolved oxygen in the tank water. For fish with damaged gills, this can prove fatal.

      What can be beneficial for sick fish that are breathing heavily is to add aquarium salt at about 1 teaspoon per gallon:

      Bulk Aquarium Salt
      If you click these links and make a purchase, we earn a commission at no additional cost to you. We use those commissions to purchase additional products to review, and to help pay the water bill around here :)

      This temporarily reduces the stress on their internal systems, and may make recovery easier. Discontinue the use of salt after the fish recovers to avoid long-term kidney stress, and never use salt with freshwater fish on a regular basis for that reason.

      Once fish start to recover, and particularly once normal black fin and body streaking indicating healing starts to appear, they should be monitored for secondary issues like bacterial or fungal infections. Those can be treated as they come up with appropriate medication, but that should only be done once breathing issues are no longer a problem.

      In order to prevent ammonia poisoning issues from returning, the tank and filter should be regularly cleaned and the water monitored for any issues with a good test kit. Cleaning should include rinsing filter media in used tank water, partial vacuuming of the substrate each water change to remove debris and uneaten food, adjusting filters so not dead spots of low flow are present, and keeping the tank well aerated with a bubble curtain or air stone if air filters aren't used already. Any dead fish or plants should be removed immediately, and water changes should not be skipped or delayed very often.

      If ammonia levels keep returning and maintenance is not an issue, check your water source to see if ammonia is present in your tap water. If so, be sure to use healthy amounts of products like Prime during water changes to detoxify ammonia long enough for the filter to process it (~48 hours):

      Seachem Prime
      If you click these links and make a purchase, we earn a commission at no additional cost to you. We use those commissions to purchase additional products to review, and to help pay the water bill around here :)

      If ammonia is still present after 48 hours and you're sure your tank is as cycled as it can be (ie, it's been 2-3 months since it was setup), consider that perhaps your filter is undersized or your tank is overstocked.

      As a final note, fear of ammonia or nitrite poisoning is the reason that a lot of modern fish keepers insist on "fishless cycling" their aquariums (cycling using ammonia or rotting food). This is not strictly required, and by carefully monitoring the aquarium waste levels cycling the aquarium with a light fish load is actually better for the long-term health of the filter. With fish-in cycles bacteria colonies establish quicker, and at more robust levels appropriate to keeping fish right away. This involves a lot more work on your part however, and is not appropriate for people who won't test their water frequently.

      Anchor Worms

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      Black Smudge

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      Black Spot

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      Body Flukes

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      Brain Or Eye Flukes

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      Branchiomycosis

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      Carp Pox

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      Chilondonella

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      Cloudy Eye

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      Columaris

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      Congested Fins

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      Costia

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      Cotton Mouth

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      Cotton Wool

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      Dropsy

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      Episylis

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      Fin Rot

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      Fish Lice

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      Floating

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      Frayed Fins

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      Gill Flukes

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      Grub (white Or Yellow)

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      Hexamita

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      Hole in the Head

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      Ich

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      Internal Parasites

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      Leeches

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      Lymphocystitis

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      Melanophore Migration

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      Monogenean Trematodes

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      Mouth Rot

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      New Tank Syndrome

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      Nitrate Poisoning

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      Nitrite Poisoning

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      Oodinium

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      Pop Eye

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      exophthalmos (Abnormal protrusion of the eyeball)

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      Rockitis

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      Septecemia

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      Stunting

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      Swim Bladder Disease

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      Methylene Blue used in a bath is often a good choice for internal manifestations of this bacterial pathogen such as Swim Bladder, intestinal, Dropsy or Pop-Eye due to its effectiveness in tissue penetration. In fact in Swim Bladder and intestinal Aeromonas infection, the MB Bath (along with possibly 1-2 teaspoons of salt and ¼ teaspoon of Epsom salt per gallon of bath water) followed by changes in water in the main aquarium, changing diet and/or withholding food for 2 days (dry foods should be soaked for 5 minutes prior to feeding), establishing a GH level of at least 100 ppm (for positive Calcium, Magnesium mineral ions) and 1 tablespoon of salt per 5 gallons may be all that is necessary for treatment.

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      Tape Worms

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      Trichondia

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      Tuberculosis

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      Tumors

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      Ulcers

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      Velvet

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      Weight Loss

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      Whirling Disease

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      Adam Till
      Adam Till

      Author



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