I saw a video of one being fed on YouTube. He had a divider holding his yellow perch back. Seems like it could be a PITA to do every time though. So I will need to give it some thoughtIMO, green sunfish and other big-mouth sunfish should be avoided if you want a grass pickerel. Tried housing three different young northern pike with green sunfish and rock bass, dont work since they keeps eat all pikes' food.