the heater is a full submersible*S* and the tank is holding a few more fish than it should be while my 55 cycles. But it has a couple Cten. 8 barilius, 3 firecracker tropheus. and a small clean up crew of some shrimp, and an oto. they are going into my 55 and a breeder pair of convicts are going into that 20Long.*S* thank you for your compliment. i just cant see setting up a tank that wasnt visually stimulating.so much more fun to watch