Swim Bladder Disorder

[Dan]

Swim bladder disorder is a multifactorial illness which primarily affects ornamental goldfish which have globoid body shapes, like orandas, ryukins, and fantails but it certainly can and does effect other fish species. You're right, it can be caused by many stress factors and the difficulty in treating swim bladder disorder lies in ascertaining which causative factor to treat.

It most often presents as a fish which floats at the surface, or a fish which stays on the bottom and doesn't seem to be able to easily rise. Most often, a fish which has normal buoyancy but is listing to one side does not have swim bladder disorder but rather, may have other bacterial diseases.

Let's talk about the anatomy and physiology of fish. The swim bladder is a small epithelium-lined sac in the anterior abdomen which is responsible for maintaining buoyancy. It has a close association with blood vessels such that gases can diffuse across the blood membrane barrier into and out of the swim bladder according to the needs of the fish. The bladder inflates if the fish needs to be more buoyant, and it deflates if the fish needs to be less buoyant. Goldfish and some other fish have a special addition to this system called the pneumocystic duct, which is a connection between the swim bladder and the esophagus, allowing additional adjustment of buoyancy by letting air out through the digestive tract.

There has been considerable debate concerning the cause of swim bladder disease. Most literature has established that swim bladder disorder may be caused by a number of potentiators including virus, bacteria or diet.

Virus: A virus can attack the epithelium of the swim bladder causing inflammation which makes the epithelium too thick for gases to diffuse into the blood system. A fish which is so affected may be stuck at a certain buoyancy because gases have nowhere to go. This may be more of a factor in non-goldfish species.

Bacteria: While bacterial infection causing swim bladder problems is rare, it is widely known and accepted that bacterial infections can cause the same kind of thickening of the swim bladder epithelium as viruses.

Anatomy: Globoid-shaped fish like ornamental goldfish are predisposed to problems with the swim bladder because their anatomy prevents normal development, and most particularly, placement of the bladder in the body cavity. This arrangement predisposes to food impactions, which in turn clog up the pneumocystic duct.

Diet: Feeding dry foods which tend to take on water like a sponge and expand in the fish can result in food impactions. I have seen a number of references on this board and others, that fish feeding at the surface will take in air with the food and this may result in swim bladder problems. In fact, this is not true. It is the swelling/expansion of food in the gut that causes impaction and it is the impaction, NOT AIR, that causes swim bladder problems.

So, how are you going to treat swim bladder disorders. There are two means at your disposal -prevention and treatment.

1. First and foremost, maintain good water quality. This will enhance your fish's ability to naturally resist viral or bacterial infections.

2. Pre-soak flake or pelleted food. This will allow expansion to occur prior to the fish eating it, and will lessen the chance of impaction.

TREATMENT:

(A) Feed your fish a couple of peas. Peas' high fiber content encourage destruction of the impaction.

(B) Fast your fish for a couple of days. Withhold all food for three or four days, and sometimes this alone will break up the impaction and return things to normal.

(C) A product called Paragon II by Aquatronics? supposedly aids in treatment of swim bladder disorder.

(D) Add one teaspoon of aquarium salt per gallon of water.

(E) Treat with Mardel's Maracyn-Two or other broad-spectrum antiobiotics.

(F) Last resort - aspiration of the swim bladder. Essentially you stick a needle in the swim bladder and suck out some of the air.