Swim bladder disease occurs when the gas-filled sac located toward a fish's tail, called a swim bladder, is compromised by stomach distension, a bacterial infection or some trauma. Certain round-bodied fish are especially prone to swim bladder disease. There are a few options for treatment and prevention of swim bladder disease, ranging from simple at-home techniques to state-of-the-art veterinary care.
The swim bladder gives the fish buoyancy and controls equilibrium. The amount of gas in the swim bladder changes as the fish moves; rising, sinking or moving forward or backward in the water. When the swim bladder is compromised, the fish is unable to control its movements. Symptoms of swim bladder disease include swimming upside down or on its side, an inability to dive or lying on the bottom. The fish may also exhibit a distended abdomen or a kinked, S-shaped spine when viewed from above
Overfeeding or improper diet is the most common cause of swim bladder disease. A fish that is given a diet solely of pellets may develop swim bladder disease because of constipation, which causes a distended stomach that affects the swim bladder. Poor water quality may be a factor in swim bladder disease, as ammonia, nitrates and nitrites from fish waste can cause a bacterial infection, irritating the fish's swim bladder. Injury to the swim bladder caused by fighting is another possible cause of swim bladder disease.
Treatment for Dietary Causes
Treatment for swim bladder disease caused by improper diet can be as simple as reducing feedings or fasting the afflicted fish for a couple of days. Thoroughly soaking pellets in water before feeding to make them easy to digest and introducing food with fibre such as zucchini, peas, romaine lettuce, squash, spinach and grated carrots may cure swim bladder disease caused by constipation and a distended stomach. Dr. Greg Lewbart, professor of fish medicine at the College of Veterinary Medicine at North Carolina State College, believes that offering a cooked pea daily helps break down impaction in the fish's stomach.
Treatment for Bacterial Infections or Injury
Water quality issues need to be addressed, assuring that an aquarium is not overstocked and has ample filtration. Fish suffering from a bacterial infection should be quarantined, and can be treated with fish-safe antibiotics such as tetracyclilne, erythromycin or minocycline. Marathon Veterinary's Dr. Doug Mader believes swim bladder disease requires a visit to a veterinarian. The veterinarian can look for infection or injury and identify and prescribe antibiotics or dietary changes. The vet may surgically remove some of the air from the swim bladder to make the fish more mobile. One state-of-the-art veterinary technique is to surgically insert a stone in the fish's abdomen to weigh it down.
Most Susceptible Fish
Certain fish are more prone to swim bladder disease than others. Round-bodied fancy goldfish such as orandas, lionheads and black moors are more likely to have problems with their swim bladders than long-bodied fish. Bettas are another fish prone to swim bladder issues.