My male guppie, Hoss, is acting perfectly normal except for one thing. His tail is getting shorter! I have him with another smaller male guppie, Little Joe. I have never seen Little Joe pick on Hoss. Little Joe's tail is still in beautiful condition! I don't know why Hoss's tail would be getting shoter! I am planning on moving them down to my 29 gallon tank. I want to know if I need to quarantine Hoss or can I move him. AND...if I DO have to quarantine him then can I put another fish in with him?( to quarantine also for the big tank.) 
