in our 55 gallon tank several of our fish are acting strange. its like their all matting on each other? randomly rub themselves on the gravel. they appear healthy and eating well. i have a 6 inch yellow and 3 inch yellow lab that are circling each other, and have spotted the yellow lab doing something the yellow tails stomach? 2 of my convicts, bumping lips together. they back up and swim into each other face again? anyone have any thoughts? theirs more weird things then besides just that. im just lost for words.