Seeing one tank mate will be a strong motivator. Assuming fish where not too dinged during capture and introduction process, they will come on to feed within a day or so. Green Sunfish, PS, and BG have been the easiest natives for me to feed train.
I like to apply small amounts multiple times per day. Fish I keep in home are trained by popping with food as soon as I get up, just before going of to work, after getting home and couple more times before going to bed. Having light on at all times during feed training is typical way I do it indoors, otherwise the complete darkness realized indoors causes stress in its own right.
Amount of feed applied is not enough to consume in five minutes. Rather it needs to be gone in 30 seconds or less. Consider blocking direct light over section of tank housing your sunfish until feed training complete.
Since many are Green Sunfish, start thinking about how to prevent jumping from tank if lid is not already tight.
