you shouldnt feed them when you first get them. let them get acclimated first and after a few months feed him. i have a rbts i got last year and it was only 4" and now its over 8" and i never fed it. it will get food from the water column or grab a stray peice of food when you feed the tank.
i just got a new blue carpet and i m not gonna feed it. if you feel like you must feed it, dont use silversides. i heard wayy to many horror stories. instead get some fresh scallops or shrimp and dice it very small to feed it.