Right now all I have in my tank is...Coral rock(gravel) a couple of pieces of the fake coral. Then I have the waterfall filtration system. An air pump in the back of the tank. I have one Percula Clownfish. It is doing really well. I used to have a problem with the ammonia being way to high and it almost killed my fish so I put it in a quarentine tank and I treated the water with Ammo lock and then some chemical, I cant remember the name right now but it was supposed to help the biological process. Now my fish is so happy. It actually swims to the top of the tank now! I also was wondering if anyone knew how to tell the sex of the fish. I dont think that my clown is the "True Percula" but I just would like ot know how to sex them. In the future I also want to start breeding my clownfish. I would like some tips on that if any one has experienced that. I have looked up alot of information on that so far. I cant wait to do that!