Ok, here's the information I have on this subject....
Whirling Disease
Signs of infection
Erratic swimming behaviour is one of the first signs of infection. Emaciation (starvation) may follow. The most characteristic symptom is a spreading pale area within the muscles beneath the dorsal fin.
Details of Infection
The causative organism, Pleistophora hyphessobryconis, is a sporozoan - a single-celled animal that reproduces by liberating millions of spores into the water. These spores are eaten with food and enter the intestine of healthy fishes. In the intestine or in the muscle, the spores turn into ameoba-like cells that spread throughout the body, forming groups of spherical cysts, particularly in the muscles. The cysts gradually replace the muscle fibres, and are released when skin is damaged or when the fish dies. Infected fishes can therefore infect other fishes and themselves again and again.
Recommended Treatment
No sure treatment has been found for this disease. There have been reports that modern anti-parasite tratments and those based on organic silver compounds are effective, but it is unlikely that heavily infected fishes can be saved.
It is worth trying to treat the water with peat and using strong filtration with a diatom filter. The first thing to do is remove any fishes with signed of the disease and then the only sure course of action is to strip down and completely disinfect the tank.
LETS HOPE YOU DONT HAVE THIS!
I have a book on fish diseases. I will see if anything matches the symptoms you listed.
