I think feeding depends on setup really.
Personally, when I had them in a 120 setup they seemed to like to get fed and grew faster when fed. Now that I have them in a 40B they ignore food, but still grow at the same rate. It all depends how well they can get food on their own. In the 120 there were fish that'd literally rip half eaten food out of their mouths so they didn't have nearly as many chances to catch what the fish were eating.