Hope you can help as am completely baffled-have 96 litre tank that had 7 platy fish in (plus some babies), one bronze cory and 5 harlequin rasbora, ammonia and nitirite very low, nitrate slightly higher (20) but not dangerously so, do twice weekly 20% water changes. Bought 2 angel fish and 2 clown loach on sunday. Clown loach are beautiful, and very active, but last night couldn't see one of them at all. Checked at 4am could still see one, but at 7am this morning they have both gone!! Surely angel fish couldn't eat them??? They don't jump out of tanks do they? No sign of them on carpet, i have no other pets! Am completely baffled! They are biggest and quickest fish in tank, what's happened ot them??