I have 2 gourami's, 2 Angel & 2 Rainbow fish have tested all my levels and seem to be good no problems. 1 of my gourami's is loosing it color and looks a little lethargic. I also have 1 of my Angel fish looks like its almost dead, both are hanging around bottom of tank. The angel fish keeps going sideways not sure what the problem is not very experienced with aquariums.