I have 6 dwarf rainbow (3 m and 3 F) in a 55g planted community tank. I've had them for 4 months with no change in stocking of the tank. Parameters are 0, 0, and >5, 78F. After the weekly 30% water change yesterday I noticed 2 of the males hovering with fins and tails moving rapidly for extended periods of time. They are still exhibiting this behavior today. Is this some kind of male pre mating behavior? Should I be concerned or is this normal? I had not noticed this behavior previously and the rest of the fish in the tank are acting normal.