I have been getting a little bit of fresh unpeeled shrimp from the local grocery store and peeling and washing it. My perc. clown fish trys to eat some of it but no matter how small I cut it up he usually spits it back out after a few chews. I think it is too meaty for him.
My puffer loves it though! I soak it in a little thawed out brine shirmp and krill to add a little more variation to the meal. I think some clam meat, finely chopped might work for some of your fish's diet, but I mainly use frozen brine shrimp, krill, and multiple flake and pellet foods. I think I will throw in some freeze dried worms in the near future.
Good luck with your fish!