Nodular white swellings on fins or body similar to Lymphocystis. This disease is more commonly known as koi herpes. Often appears with a lumpy cauliflower like appearance. Usually starts out white but as it grows will become red and angry looking.
Glugea and Henneguya are sporozoans that form large cysts on the fish's body and release spores.This disease is becomming more prevelant in koi. The fish bloat up, with tumor like protrusions, and eventually die.
There does not appear to be any link to water conditions as this disease has been found in the cleanest and best maintained ponds as well as absolute quagmires.
Some claim that the use of acriflavine will provide results, but the jury is out on that one.
No cure, as of yet. It is best to destroy the infected fish before the spores can spread.