They will eat pellets. Second best option is large frozen foods like mussells and shrimp. I wouldn't do freeze-dried, frozen is more nutritious. You can even use stuff from the seafood section at the grocery store. The problem with any whole food like that (live, freeze-dried, or frozen) is that it is not a complete and balanced diet. Try to get them on pellets, keep trying if they don't take to it right away.