My copperbanded is rubbing against the rocks but I spent more than one hour looking for any parasite and I could not see any.... Is there another possibility besides a parasite?
A lot of parasites aren't visible, and sometimes they scratch if it's internal parasites (no logic to this). It could be a range of things, from ich to flukes to some detritus irritating the fish. Unfortunately, it's going to be near impossible to identify without visible symptoms. My hunch would be a minor outbreak of ich or flukes (which are often small and transparent and lodge under scales).
It also depends a little bit on what kind of fish it is and what kind of tankmates they
are living with. Sometimes they do it to show displeasure or territoriality. But as Len
said, 95% of the time, it is a parasite, and you can't always see it. My Lunare Wrasse
flashes when I feed the tank, especially when I feed flakes which he least prefers. I think
he gets pissy when someone is eating and he is not. But I also think he has something
going on that I can't see.
