Anyone who keeps a tropical fish aquarium needs to be familiar with the diseases that can infiltrate the tank. One of the most common of these diseases is swim bladder disorder. In her article "Swim Bladder Disease", Rachel Hunt writes, "Swim bladder problems are not contagious, they don't seem to be painful, they are generally easy to treat, and they are usually not even close to fatal."
What is a Swim Bladder?
The swim bladder is an organ in fish that is responsible for their buoyancy. When the fish wants to rise to the surface, the bladder fills with gasses. When the fish wants to sink toward the bottom of the tank, the bladder expels gasses. The article Swim-bladder disease on the Aquatic Community site reports, "If the fish somehow gets an injury or disease to its swim bladder, regulating its buoyancy will be hard or impossible for the fish."
If you find a fish floating at the top of your tank, but it isn't dead, that's a good sign it has a problem with its swim bladder. Conversely, if it sinks to the bottom and can't seem to swim back up, then that's another sign. Fish with this disease may also have a problem swimming. They may end up swimming upside down or on their sides. Some fish may also have a swollen belly.
A number of different conditions are behind swim bladder disease. The most common is constipation The number two cause is some kind of physical trauma to the fish. Perhaps it jumped out of the tank or was beaten by another fish. This may bruise or rupture the swim bladder. Bruises can heal but a rupture cannot. Other causes are a viral, bacterial or parasitical infection as well as toxins in the water.
Treatments - Check the Water
First you will want to test the water in your aquarium for pH, high ammonia, nitrite or nitrate levels. Also check the level of chlorine. In her article "Swimbladder Disease" Dr. Barb writes, "Proper water oxygenation, partial water changes and use of appropriate water conditioners may help."
Treatments - Constipation
Just like people, fish get constipated if they eat too many rich foods and not enough fibre. In the article Constipation Information and Symptoms, Rachel Hunt writes that you can tell if your fish is constipated if it has "... a swollen tummy (the area right behind the ventral fins and right in front of the anal fin), loss of appetite..." The best treatment is preventive--make sure you feed your fish a well-balanced diet, keeping rich, fatty foods to a minimum.
Treatments - Bacterial Infections
If your fish is wobbling around the aquarium, it may have a bacterial infection known as whirling disease. This you can treat with TMP Sulfa or Erythromycin. If the swim bladder contains a yucky fluid you need to use quinine sulphate. If the back part of the fish's abdomen is inflamed and it's standing on its head, you can use TMP Sulfa or Sulfa 4 TMP.