If its healthy and assuming you have stuff for it to "pick at" (its just grazing on algae) on the rock they all will do this. Not that its any of my business but a 29 gallon is too small for a tang. Good luck.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.