My clown knife, like all others, goes up for air quite frequently. I got used to it durring the night and it didnt wake me up. Until recently. Since I transfered him from my 55 gallon to my 90 gallon he has started going up for air really fast and breaking the surface on occasion. It is really loud and splashes water around. Is there any way to discourage this behaviour? I tried putting floating plants across the surface but he still did it.