I recently purchaced a rubber lip pleco from petsmart and in a couple of days little white spots started showing on it in just about a week my spoted cory had them and something on his fins that looked like velvet.now it is visable on my glolights one has died along with the cory and rainbow shark.it's a 55gal. fully planted tank so salt or anything else I know of is out of the question.I was wondering if when they alldie off which they most certainly will ifI add a uv sterilizer would that prevent from coming back and not getting anything ele from PETSMART if so what size would be best 9-18w,and how long wait to restock to make sure it's gone. second time this has happend.:help: