Freshwater Fish Disease

Jellyfish, Colorful, Fish, Pretty, Tank

It is a nice lazy day and you are just kicking back and enjoying the aquarium you have worked so hard to prepare. One of your fish looks like he has been rolling in the sand. And yet another appears to have less fins than you recall. And still another is bloated he looks like he is going to burst. In general, it looks as if your fish are sick! Paradoxically, keep fish long enough and it is something that you’ll have to face eventually, and usually fairly early sadly. You see, illness is often preventable, but we just learn how to do this after doing it wrong the first time. Many disorders can be turned around if seen early and treated correctly.

So how do you tell that a fish is ill in the first place? It’s not like they are going to tap you on the shoulder and allow you to know. For the most part the only way you’ll know something is wrong is through careful monitoring of the appearance and behaviour. Hopefully you are already pretty well acquainted with what might be considered normal for your fish and can thus see if something is off.

-paleness/Possum Droppings

-clamped fins (the fins are held near the body)

-scratching or rubbing against objects in the tank

-heavy breathing


-decreased activity

… and of course the more obvious signs like visible swelling, nausea, and such.

Try to have a few minutes every day to check for any signs that something is amiss. A disease caught early is much easier to treat and the odds of the affected fish surviving the ordeal are much greater. For many ailments your fish may face by the time it’s blatantly obvious it’s too late.

Obviously one step better than treating your fish as soon as they get ill is preventing it from occurring in the first location. A quarantine tank is basically only a tiny bare bones aquarium set up where new arrivals can spend a week or 2 before entering your main installation. This gives you ample time to be certain that your fresh fish are in good health before they have an opportunity to possibly spread any diseases to your other fish. Additionally, it gives new arrivals a opportunity to get over the stress of going in a quiet and serene atmosphere. And if a problem does arise with the shredder already isolated makes treatment much easier also. Finally, in case a problem does hit the fish in the home aquarium the septic tank can serve as a hospital tank also, preventing the further spread of illness and providing a safer and more controlled environment for the use of any remedies.

Besides a quarantine tank, maintaining your fish in good overall health goes a long way towards preventing any illness from taking hold. Most frequent ailments often arise in fish only if their health is already compromised. What causes their health to become endangered? Nearly all the time the offender is poor water quality. A fish trying to reside in filthy water in kind of like you trying to live in a home full of smoke- it is unlikely you’re going to be in the best of health. Keeping on top of your aquarium installation’s maintenance is crucial to keeping your fish healthy and disease free. Therefore, if your fish ever become sick your first step should be to ensure that the water is in great condition. All the vital parameters, such as nitrate, ammonia, pH, and temperature, should be assessed. Always be leery of any equipment or decoration that has been recently added to the tank as well which might be leeching something poisonous into the water. Andif poor water quality is not the origin of this illness, a water change is never a bad idea once it comes to retrieval the cleaner the water the better.

Often people go straight for the drugs at the first sign of an illness in their fish, usually without even knowing what precisely is incorrect. This isn’t a good move. Positive identification of a disease is absolutely essential before beginning program of any medication. Many medications are not just easy on your fish meaning using the wrong one could wind up further stressing your fish without treating their illness, probably resulting in death. Still, in case you encounter a disorder where a drug is appropriate it can be a true life saver. Just be certain you remove any carbon from the filter prior to beginning treatment because it will soak up the medicine until it has an opportunity to act. And, it should go without saying that the instructions should be followed to a T. Pay special attention to any warnings dealing with species that the medication shouldn’t be used with. Some, for instance, will kills snails and plants if there are some from the tank.

There are tons and a lot of ailments your fish may face- much more than what are listed here. However, many are fairly rare, affecting just a few specific species or just arising under specific conditions. Instead, this list attempts to cover just the most frequent ones that most aquarists have a tendency to run into.

As the common name of’new tank syndrome’ implies, this is typically only a problem in recently setup aquariums, though it can happen is older systems when the filtration system is badly damaged. Some are really quite useful, and necessary, to your aquarium. Their task is to process the fish’s waste from highly toxic substances, namely ammonia, to compounds they can more easily withstand. The process of establishing these germs in a brand new system is called cycling. Unfortunately, this measure is often skipped resulting in a buildup of ammonia that in short order contributes to dead fish.

Remedy: water changes

To solve this issue you basically just need to keep the water clean through regular water changes before the bacteria have established themselves and may take over. A test kit for ammonia is quite useful here as ideally you would like to keep the ammonia level under 1ppm. Typically you’ll have to do a small water change daily for a couple of weeks to enable the cycle to finish while maintaining the tank habitable to your fish. Keeping feedings light in this time may also help keep the waste load low which in turn keeps the water cleaner.

Signals – fish has fuzzy whitish globs or stains attached to its fins or body

Just like a lot a ailments you are going to experience, fish fungus usually appears on fish whose health is already compromised. This normally would not be a issue, but if a fish is already in poor shape the fungus can find a grip very easily. It often begins at the website of an accident, which may be anything from minor scrapes to significant sores, and spreads quickly from there.

Remedy: medication for fungal infections

The best way to treat fungal infections is with drugs developed for them. Obviously making sure the tank is in great shape is key and the fish is probably already in poor shape and needs all the help he can get recovering. As a side note, many treatments for fungal infections also work against bacterial infections that could bring some extra advantage if the fish’s initial poor health was caused by one.

Signals – fish is coated in lightly colored specks or has a dusty look


Ask people to name a frequent fish disease and ick is most likely the one that you’ll get. It appears just about everybody who’s ever maintained fish has had to handle it at some point or another. What’s more, it’s quite easy to see compared to other diseases and so appears to stick with people. When you haven’t encountered it before, ick is a parasite that burrows into the fish’s skin causing small white spots which make it appear like your fish was salted. Outbreaks often occur following the accession of fresh fish, which attract ick and them, though it can also limp along in a tank for quite a very long time until conditions are favorable for a burst. Like nearly every disorder, favorable conditions means fish in poor health with the most frequent reason being poor water quality.


It is another parasite that acts much like ick, appearing as stains on the skin.

Remedy: medication for parasites

They are both parasites using a similar life cycle- part of that is attached to a fish and part of which will be spent free swimming. Killing them is more or less impossible while they are safely burrowed beneath the fish’s skin. It is only when they emerge into the open water to search for a new host that they are vulnerable. This means treatment can take a while. Medication has to be implemented for an elongated period to wait out the parasite’s natural life cycle, which may take up to a month. Raising the temperature of the aquarium a couple of degrees can help speed things up a little. So, in case you move all of your fish to quarantine for therapy, any parasites left at the primary tank will perish after about a month.


Signals – fish is bloated, and possibly with the scales giving it a pine cone look

Dropsy is not a disease itself but rather the physical outcome of another ailment, usually a bacterial disease though it could be brought on by any number of different things. The swelling is caused by by a buildup of fluid in the fish’s body cavity.

Treatment: medicine for bacterial diseases, aquarium salt

Unfortunately by the time the signs are clearly visible it is often too late to save the fish. Still, the best strategy is to move the fish to quarantine and start administering an antibiotic, rather in the shape of an medicated food. Adding a little bit of aquarium salt may also help the fish expel some of the extra fluid thereby relieving the swelling. Use approximately one tablespoon per five gallons.

Signals – fish has difficulty maintaining equilibrium and may have difficulty controlling thickness

A fish’s swim bladder is kind of like a ballast tank in a submarine, just with air rather than water. They use it to keep themselves upright and in the appropriate depth. If it becomes damaged or otherwise perturbed the fish is no longer able to restrain this air and so will typically either sink to the bottom or float to the surface, often in an off-kilter orientation.

Remedy: fasting/cooked peas, medicine for bacterial diseases

Unfortunately there’s not lots of consensus on the specific cause (and in fact there are at least a few possible causes) or how to deal with it. Ensuring the tank’s chemistry is in great shape should be your very first step of course, as it should be with any difficulty. One frequent cause is a blockage in the fish’s digestive tract. The typical solution for this is shelled cooked legumes (they are sorta the go-to fish laxative). Backing off feedings for a couple of days can also help. If not then it might be the symptom of a larger disease in which case a drug can be attempted. Unfortunately it can also occasionally arise because of injury sustained during transportation in which case there is not much that could be accomplished. In these situations all you can do is give the fish a place to recuperate and hope for the best.

Signals – fish includes a protruding eye

A pretty self explanatory title, the fish’s eye or eyes bulge out of the fish’s mind as though they’re on the brink of falling out entirely. Once again this is not so much connected to any one particular cause but rather might originate from a few possible resources, namely injury or an illness.

Injury due to fighting or from bumping into something is most likely the most common. In cases like this the best you can do is prevent any fighting and supply your fish with a calm home to recover.

Another possibility is a bacterial disease. If both eyes are popped then this is much more likely, although the fish should still be assessed for signs of injury or fighting. A fantastic medicine is the best course of action here.

Add 1 tablespoon per five gallons and watch to find out if it has any impact. Bear in mind this can help alleviate the swelling but will not resolve the underlying problem and as always your first step should be to guarantee that the water is in great shape.

Signals – fish has a cloudy eye

The creatures of the world have all kinds of interesting eye with assorted colours and shapes and whatnot. 1 thing they all have in common, however, is that the center is clear and nice. Should you ever notice your fish’s eyes or eye getting milky then something isn’t quite perfect.

There are a handful motives a fish’s eye may become cloudy. Parasites or germs are possible causes, especially if the eye was hurt. Poor diet or even cataracts because of old age are potential culprits also. However, the most probable cause falls based on so many different issues – poor water quality. Getting the tank is fantastic shape should be your first concern if your fish develops muddy eyes. Pay special attention to the pH as a particularly low pH is considered to contribute to this issue. Check that you’re feeding your fish an proper diet also. Together with better water quality and a suitable diet the problem should clear in a couple weeks. However, if the issue does not clear after a few weeks with enhanced conditions an antibiotic could be attempted.

Hole at the Head/Lateral Line Disease

Signals – fish has holes in its head

The title is fairly self explanatory, and the indicators are simple to spot, so all that leaves is the cause. Why are there undesirable holes on your fish’s head? Unfortunately there is no consensus on the precise cause. It may be brought about by some particular pathogen, but none has been identified as of yet. Some think overuse of activated carbon or nutrient deficiencies might have something to do with it also.

Remedy: improve conditions, diet modification

Ultimately, the best course of action is to enhance conditions as much as possible for your fish. Measure up the water changes and try removing any activated carbon out of your filtration. Try to include as much variety to your fish’s diet as possible. Frozen in addition to vitamin enriched flake foods are fantastic sources of vital nutrients that your fish might be lacking.

Signals – the fish’s fins are deteriorating

Fin rot is another disorder that isn’t so much about a particular contagion as opposed to a consequence of the fish’s overall health. Fin rot typically only affects fish which are already worried or weak because of something else like poor water quality, malnutrition, bullying, or perhaps some other illness, at which point bacteria move in and begin feasting on your bad fish’s fins.

Your first course of action should be to ascertain the fish’s health has slipped in the first place and fix it. Check the water quality and change to high quality vitamin supplements if you have not already.

Again, most the time health problems come down to a water quality issue. Keeping on top of your aquarium maintenance program is the best way to prevent problems in the first location. Likewise, if an illness should attack assessing the water parameters should be your first step. Many problems will clear by themselves with improved conditions. And when a drug becomes necessary make sure to follow the instructions extremely closely. An overdose of medication can be just as bad if not worse than the disease itself.

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