My blue tang acting wierd...just started my tank about 6 months ago...got my blue tang 3 weeks ago. Tang want cool until 2 days ago..it just stay in the same spot on my live rock..looks dead but isn't.all water parameter are at zero. Yellow tail demsal was bothering him at first but stopped about a week after...dont want this lil guy 2 die...it lost a lil color and dont think it has ich...help please...