How many times a day should i feed my two fiddler ?

I have had my fiddler for two days now and i have been feeding them every nite at 7:30, i feed them two little pieces of shrimp pellets each. But they seem more hungry then that, later i watch them feed off the floor like little organisms or something........and for later when they get comfortable in there new home i bought them silver sliders (frozen, dead) i figured i could just rip off a piece and drop it in their tank, and little brine shrimp (frozen, dead) are those healthy, and good snacks for them??, thank you for your help. Jordin