the answer depends on what species you desire to bring into condition.
I will asume you ar refering to the Blue Gularis.
The answer is everything as long as it is good quility and lots of it.
I feed blood worms, water fleas, mozzy rigglers and a high quality flake, you could also feed trimed beef heart.
You should also give them all they will eat this species is a big eater , to save money top up there feedings of live or frozen insects with flake and beef heart.
you may be shocked as to how much food they can chow down, especially as your fish are still growing.