chocolate chip starfish-I guy frozen shrimp, thaw it and give it to him when he comes to the top
Arrow crab-shrimp pellets and algae wafers.
I am no pro...you will probably get lots of better advice!!!!
I feed mine what is left over from food and algea they find. And I make my crabs happy by giving them a piece of shrimp every now and then. And I use a scewer to feed my "serpent" star I feed him shrimp or squid.
Research what you have.
I would suggest shrimp or some other meaty food for the carnivoris type.
Dried seawead for the herbivoris types.
And bolth for the omivoris types.
You wont have to feed my dried see weed cause they will eat algea and left over food to. Some snails will even eat lettuce.
For the filter feeders I would go with kent "what ever you choose" they seem to be the best.