Ich can be anywhere that is wet, sand, rock, water, fish, depdening on stages of its life cycle. The following diagram shows the life cycle of ich and normal time it spends on each cycle. In the tomont stage, ich can attach to sand, rock, coral or tank bottom. Also there are some information in the last few years suggest that the tomont stage can last up to 72 days (vs. 28 days in the diagram).
