ok, here goes. i Have a juwel vision 260. cycled and everything. I have had 3 clown loaches in my tank for the past year no problems at all. The 3 of them happily swimming together. they are about 4" long. They ave lovely deep black an yellow markings an the fins are nice and red. the picture of health. HOWEVER! tonight i looked into my tank and two of them are a blacky colour, well still yellow an black but a fair bit grey looking at least. they seems to be fighting, mouth to mouth an nipping at each other too. my 3rd clown loach looks the picture of health an is staying well clear of the other 2! wat are they doing HELP!