Since FB isn't about at the moment, I can field this. Firstly, what sort and size of feeder fish did you use? Goldfish feeders are actually almost anti-nutritional, so avoid those and go with feeder livebearers like guppies/mollies/etc.
Size of feeders will certainly affect how much and how often you feed. I have now raised 4 batches of senegal fry, and it is pretty difficult to overfeed them...they quit eating when they are full....however, leftover feeders will affect the tank bioload, so try to not dump in too many at once. As well, since variety is the spice of life and the basis of a healthy diet, also use other live foods such as blackworms, earthworms, ghost shrimp, small aquatic frogs and tadpoles (assuming you can get them from a safe source); and frozen foods, such as bloodworms, mysis shrimp, krill, etc.
The varied diet, along with lots of partial water changes and good filter maintenance will see your 4" and 6" Senegals at 8" and 12" in just a couple-three months...their growth is explosive as youngsters.
