Our lion's head fish has difficulty with staying down in the water. It keeps floating to the surface of the acquarium. It uses a lot of energy to swim and stay down, so that once in a while it even goes belly up or floats on the side. It's eating o.k. It just keeps floating to the surface. It's a strong fish. How do we treat it?
We have a 200 gallon fresh water aquarium with about thirty tropical fish: angel fish, gold fish, lion's head, etc.

We have a 200 gallon fresh water aquarium with about thirty tropical fish: angel fish, gold fish, lion's head, etc.