A red fish swims through dark water.

When Your Fish Can’t Swim

Does your pet fish have trouble swimming? If your fish floats on the surface or has a difficult time rising from the bottom, he has a buoyancy problem.

Buoyancy trouble is a common and widespread problem. A recent study published by the Japan Aquaculture Society Journal described the condition in detail and named this syndrome “tenpuku” disease, which means “capsized.”

Buoyancy problems are caused by a wide variety of disorders. Some of these include systemic disease (bacterial, viral, fungal, parasitic, cancer), starvation, general weakness, eroded fins and broken fins, swim bladder diseases, and excessive air in the gastrointestinal tract or abdominal cavity. Buoyancy disorders of goldfish, especially the round-bodied ornamental varieties like orandas, lionheads, bubble-eyes, Ryukins, and moore, is one of the most common and frustrating problems confronting the pet fish hobbyist and aquatic animal veterinarian.

Swim Bladder Disease

Many buoyancy problems are simply idiopathic, which means that there is no known cause, and are associated with the swim bladder – a small epithelium-lined sac in the anterior abdomen responsible for maintaining buoyancy. The sac inflates if the fish needs to be more buoyant and deflates if the fish needs to be less buoyant. Goldfish and some other fish are members of the cyprinid (minnows and carp) family and are physostomous, which means there is an open connection between the esophagus and the swim bladder. The bladder is called a pneumocystic duct, and it allows additional adjustment of buoyancy by letting air out through the digestive tract.

Sometimes the swim bladder is affected by food impactions. Viruses and bacteria can inflame the lining making it difficult for gases to diffuse across. And the genetically selected rotund body type of the goldfish predisposes them to food impactions, which in turn clog the pneumocystic duct. Then, too, feeding dry foods which tend to take on water like a sponge and expand in the fish helps to cause food impactions.

What To Watch For

Your fish will show signs of difficulty swimming or staying afloat. Some things you might notice are:

Veterinary Care

Green Pea Treatment

Preventative Care