You can feed them small pieces of store bought seafood like salmon, shrimp, scallops just make sure there are no preservatives. You can also feed them mysis shrimp or frozen mix food like LRS or Rod's. I wouldn't feed them more than once or twice a week. They will also catch food that you're feeding to your fish as it floats around the tank. With anemones if you feed them a lot, they will grow bigger. So if you have say a small BTA just feed it every three days or so and it will grow faster. Watch it because BTA's can and will get HUGE, or they can split if you over feed them.