I have a working hypothesis that RES are much more light sensitve and dark adapted than other sunfish, so far it seems to have worked well with pellet training them. Prior to my winterkill I had good numbers of RES eating floating pellets off the surface in my pond in the evening in the shaded area of the pond.

One of the things I did this summer was to have an automatic feeder dump small amounts of non-hydrated floating feed in the tank evey hour during the day while the bright light was on while I was away at work. I also would feed hydrated pellets after cleaning the tank when I got home while the bright light was still on, they would eat everything but my best feeding responses always came when the bright light was off.