Swim Bladder Disease

Symptoms

Swim bladder disease is very easy to identify. It will cause fish to float, sink, or swim oddly, depending on the cause. In minor cases, it can be as small as a little difficulty in swimming all the way to completely hindering the fish's activities entirely. The fish will also act more lethargic, as swimming will take far more energy than normal. 

In most cases, swim bladder disease is only a symptom of a larger problem. It can occasionally become infected, but most issues will stem from an outside factor. Buoyancy is directly determined by the volume of water an object displaces. If something puts pressure on the swim bladder, it will decrease the volume of water the fish displaces, causing the fish to lose buoyancy, and cause it to have to work harder to stay afloat. If the bladder becomes over inflated, the fish will displace more water causing it to rise towards the surface against its will. The direction in which the fish is pushed or pulled will help you to determine the cause of the issue.

Causes

Swim bladder disease is often a result of poor water quality. If ammonia levels are too high, it will greatly impact the ability of the fish's blood to carry oxygen and other gasses, meaning that the swim bladder will be slow to change or get stuck at a certain volume. Constipation is another common problem for fish. When fed only dry processed foods, such as flakes or pellets, fish will become constipated over time. This will put pressure on the swim bladder, causing the fish to sink. Dwarf Gourami Iridovirus is another cause of swim bladder disease. As the spleen swells to a massive size, the dwarf gourami will get stuck at the bottom of the tank, causing it to drown, since it needs to breathe atmospheric air. Dropsy will interfere with the swim bladder, as will a whole host of other issues. 

Treatment

Treatment will vary based on the cause of the swim bladder issue. The first thing to check is always the water parameters. If your water is not good for the fish, a water change should have them happy and healthy again. Diagnosing the problem with the filter bacteria would be the next step on that. Constipation is easy enough to clear up. If it's a mild case of constipation, switch to frozen or live foods such as brine shrimp or bloodworms. If it's a more serious case, an Epsom salt bath will give more immediate relief. 1 Tablespoon per gallon (~4 liters) of water in a separate container for 15-30 minutes will do the trick. Following the bath, a change of diet is essential to keeping fish healthy and happy. Processed dry foods aren't bad as part of a complete diet, but when used as a staple, they can cause issues. 

Other causes will require special treatment. Internal parasites can cause swim bladder disease. Praziquantel would be appropriate in this case. Bacterial infections in the bladder itself or in other internal tissues can lead to swim bladder disease. General antibiotics, for both gram positive and negative bacteria, are the best course of action. Some diseases, such as dropsy and DGIV, and other congenital issues don't have a good treatment. All that can be done is to let nature run its course or euthanize the fish. 

In some very minor cases, swim bladder disease can clear up on its own without intervention. If a fish is still eating, is able to swim, and is otherwise healthy, the only real reason to treat it would be because of bullying. However, if the disease progresses any further, intervention will be necessary. This best case scenario is just that; best case and is usually not the case. A keeper's best judgment ought to be employed when dealing with swim bladder disease.