I just watched my bigger RES kill a rather large rosy feeder fish. It took him five minuets to kill and eat the head. Thats when my smaller RES came over and bit on. Then they both started swimming as fast as they could. And it looked like while they where swimming they where clawing each other.

There is no sign of damage on either one, but is this fighting over the fish? Or where they trying to use teamwork to tear it apart?
They have never fought before, but if this is fighting what should I do about it?
Thanks in advance,
Nathan Radle.