I currently have four clowns in my system. 2 regular ocellaris and two black and white. Havent had any problems...yet. They have started hosting my (small) BTA after two months, but only at night. And I say "they" casue it appears that they are taking turns. The funny part is that during the moon light period is fine the BTA is open and one of them goes in. It is when light go out that the BTA closes up and they are still there tring to get in. I have since bought a large green BTA but they want nothing to do with that one. Is this normal????