Empty hook, fish are extremely hungry or not used to hooks. Bottom line, in the wild, either the fish strike whatever hits the water or they might not eat.
I am a little biased here about the sunfish and bullheads. I currently own bluegills, warmouths, greens, shellcracker and yellow and brown bullheads. These fish never disappoint in interaction, tenacity, color and antics. I can tell the difference between them all. There is something unique about all of them even though many come from the same species.
No heaters, no disease, minimum or no parasites, extremely hardy and very easy to feed.