I have a cobalt blue dwarf gourami that I have had for about three weeks. He doesn't have any external symptoms, other than perhaps breathing little more rapid than usual. But the thing that worries me is that he is constantly swimming up and down the glass on one side of the tank. He eats like a horse, so he definitely isn't starving. Do you think perhaps he has an internal parasite that is stressing him? Or do all gouramis swim like that? His tank mates are 4 white cloud mountain minnows, 3 cherry barbs, 2 cory cats, one Pl*co, and a Thai wood shrimp. My ph is exactly 7, ammonia and nitrite are 0, nitrates around 10. Any suggestions?