Blue tang acting weird

[mantis man]

My friend just purchased a blue tang, lately the tang began to 'scratch' himself against things in the tank. first it was some rocks and empty shells, today he went next to his clown fish and began doing the same. at some point the clown starting raming/biting the side of the tang and continued to do so for some time. what could be the problem?

 

[elfdoctors]

Welcome to the boards!
Does your friend quarantine? Tangs are notorious for introducing ich into a tank. Rock scratching is a common early sign of ich.
It is also possible that the fish are merely adjusting to each other.

 

[mantis man]

the tang was bought froma respectable local fish store that had at leat 5 other tangs and another 5 varied fish in teh same tank. but my friend has had ich in that tank before... he treated it completely about a month before he got the tang. it may just be that they are getting used to each other. ill have to tell him about the ich warning though
thanks for the welcome, personally im getting money ready for a mantis shrimp tank (20-30) nothing big, my first tank.