I'm planning on getting 6 or so cory cats. In general, is there an ideal ratio of males to females? Do they do better with more females to males? Other way round? Pairs? Irrelevant? Single sex groups OK? Obviously the latter won't work for breeding purposes LOL , but I'm not too worried about running a successful breeding programme per se - more concerned with their general welfare. Although I do recognise that a sign of happy and succesfully kept fish may well be their desire to make more fish.