Variety is the spice of life, including for fish. The puffer would appreciate any large meaty things: krill, silversides, prawn. I'd suspect that Clown would also. Otherwise, a decent LFS will have a variety of things in their freezers: Formula 1, Special Formula VHP, Prime Reef, Marine Cuisine, Mysis, Mussels, Clam, etc. etc. You can also give them dried foods on occasion (soak it in tank water before serving) like Plankton, Pellets, flakes. Just mix and match. My freezer generally has as much fish food as it does human food. I'd say the variety I offered was so big that they didn't eat the same dish more than 3 times a month!
As far as brine, live brine shrimp is like eating popcorn. But the frozen or freeze-dried varities tend to be sold enriched, so the fish will be getting some vitamins.