I hear all the bashing of feeding gold fish, but I have to say that I have a Clown Knife that just turned 20. 20 years and he's been eating goldfish since he was big enough for them instead of guppies. He got ick right after I put him in the tank when I was 15 years old. That is the only disease he has ever had.
That being said, having owned a RTC in the past I would recommend getting him off the feeders as fast as possible. Too expensive for that voracious appetite. I fed mine everything. Bits of steak. Albacore tuna (packed in water not oil), feeders once in a while, cichlid sticks, whatever...And I could feed him that stuff from my hand. It was too cool...Closest thing to a puppy you will ever have in a tank unless of course you drain the tank and add a real puppy...