Mine take everything.
I have x 2 CK's at approx 12-14" & RCK at 11"
They take Big Prawns, shrimp, Pieces of white fish, Earthworms, they also love Mascivore & sinking sturgeon pellets.
The RCK will even take floating Hiakri Cichlid Gold from the surface, little trick he learnt when he was kept with Big lemon Barbs
They can be finicky feeders when small but will copy what other fish in the tank do & should eventully take most foodstuffs.