Although all fish can get swim bladder disease, sometimes called "flipover," such problems occur more commonly in fancy goldfish such as orandas, fantails and black moors. As "short-bodied" goldfish, their body shape predisposes them to the condition. Goldfish can live several months with a swim bladder problem, but it can be treated, and extra care can reduce their chances of contracting it.
Most fish have a swim bladder, also called an air bladder. Part of the digestive system, it contains oxygen, or gas, that allows the fish to climb and dive with ease in the water. Problems arise when the fish's digestive system becomes clogged with food or by tumours or other growths.
You can easily tell when a goldfish experiences distress related to a swim bladder problem. Such a fish might cling to the bottom of the aquarium and have a difficult time rising to the surface to feed. Other fish display erratic, lopsided swimming patterns, float upside down or list to one side.
Goldfish raised for pet stores first live in ponds, where they have a natural diet. When introduced into home aquariums and given commercial food, problems can arise from the change in diet, as new food blocks the fish's intestines. Supplementing commercial food with frozen brine shrimp, available in many pet stores, can help. If the culprit is a tumour, cyst or other growth, veterinarians can perform surgical procedures to get rid of the blockage. Not all goldfish owners can go this expensive route, however.
For swim bladder problems caused by food, pet owners can exchange 50 per cent of the aquarium's water with fresh water of the same temperature without too many nitrates. (Pet stores sell simple, inexpensive test kits to check for nitrates.) Refrain from feeding the affected goldfish for two or three days, giving the fish an opportunity to cleanse its own system. When feeding resumes, improve the fish's diet.
Frozen peas can also help, says veterinarian Douglas H. Thamm. Mash a few defrosted peas (or beans or zucchini) and feed to the goldfish. Remove any uneaten vegetables from the tank. Take care not to overfeed your goldfish, and provide just enough food for the fish to eat in a few minutes. Food that floats to the bottom uneaten fouls the water or causes fish to overeat, which only compounds swim bladder problems.