exotickeeper
Member
There are several causes of ick. One of the most common is stress, when marine fish gets stressed then an outbrust of ick can occur. Other ways are through contraction from one fish to another, by introducing new fish into an aquarium without proper acclim. or quar. Ick occurs in stages, but in simple terms ick is spread by having free floating ick, the ick is floating in the tank, it has approx. 3 days to find a host, WHEN it does, the ick multiplies. Otherwise, in those rare instances where ick doesn't find a host, then it dies off.