I'm planning on setting up a Dwarf Cichlid tank. This will be my first attempt at Cichlids. I'm getting a 50g and a 60g, but am not sure about which would be the better choice. I plan on either getting a biotope with Cockatoo Cichlids, or Julies. The Cockatoos, if I can find them and they are within budget, will be in a biotope tank. What exact fish share the same space as them? Will they eat ottos? Do they need sand, and if so how deep? Do they need a strong current? Will a sponge filter attached to the intake of a canister filter prevent the sand from gumming up the canister or damaging it? Any fish suggestions to make it look natural? The Julies are my second choice, I'd much rather have the cockatoos.