Why is it that my G cat is always going to the top of the tank and slurping at the surface? It's really annoying, being next to the bed, and I have no clue why he does it. I was thinkin of rigging up some egg crate at the top so he can't get there, and building a canopy to cover it, but don't want too if it's beneficial to him. What the hail is it doing?!