mixed diet of whatever you can get them to eat shrimp, prawn, smelt, pellets, beef heart, chicken liver, worms, whatver you can get them to eat. as most people say feed them every 3 or so days. either feed everything on that day or make 1 day one thing and then the next feeding day something else, this will ensure that they have a diverse diet and get all the nutrients and vitamins they need. Your cats are still a little on the smaller size for their species so you could even go as far as to feed them every day. however that will cost you more and dirty your tank faster so its whatever you want to do. I have a 4in rtc which i feed blood worms, omnivore pellets, and smelt twice daily. hes growing fast