There is no singular cause for Hole-In-The-Head Disease, and there are some species of fish that seem predisposed to it, such as
Tangs and Surgeonfish. Although occasionally caused by a parasite (
Hexamitid spp.), it is not commonly found with most infections. Many stressors, such as poor water quality or diet, can start the chain of events that lead to Hole-In-The-Head Disease.
Other possible causes or influences on the progression of Hole-In-The-Head Disease include:
[/QUOTE
]i put a bag of something with carbon on it, but I been loosing fishes even prior to Saturday when I did the water change