my coldwater tank on my signture is what im on about. One of my goldfishs and one of my comets and my schbkin keep floating to the top and then swim down but keep floating to the top. i have two fluval 3 pumps and a airpump could that be the problem tho much air or could it be somthing to do with the swim bladder? or somthin else? and how can i stop it? 8)