You said he's 5-7 inches. Its definitely time to move him to a bigger setup before stunting sets in, if it hasn't already. Glad to see he's eating a decent diet now. I also wouldn't feed him frozen food, I would definitely defrost first. Uncooked market shrimp with the shell on is great, scallops, mussels, clams, crab legs, big snails, crayfish. All good choices.