Ok, so I have a 90 gallon African tank that's been going for about 5 months now, and I've been looking for something to fill in the top area of the tank. So far, the only fish I've been able to find that would work are African butterfly fish. Right now, the tank is stocked with Congo tetras and a pair of leopard ctenopomas taking up the mid-level and a group of synodontis petricolas on the bottom. For anyone who has experience keeping butterfly fish, my question is this: do they do well in a group, and if so, about how many would be suitable for a tank this size? After reading up on them, I've been finding a lot of conflicting information, with some source saying that they're aggressive towards their own species, and others saying they aren't, so I'm hoping to hear from someone who knows their stuff about these fish.