Seems like all my creatures love my heater. My crabs like to jab at it and my snails like to cruise around on it. However, now my clown appears to be following the trend. I got my clown about 5 days ago. He is eating wonderfully and likes to poke at things in the tank. But I just have one small concern. He really seems to like hanging around my heater. His favorite spot is at the very top. He likes to nip and rub against it, is this normal behavior? He spends lots of time there, but will also take small trips around the tank.