I fed actual frozen shrimp before, about medium size. I kept them in the freezer and at feeding time I would take out one and I'd try cutting tiny pieces off but I'd end up using my nails because I tried getting small pieces enough for my Bettas mouth, he would definitely eat the pieces small enough for his mouth. Then I switched over to Hikari frozen brine shrimp, all tropical fihs love it. They come in cube trays but one cube is way too much for a single Betta meal so u have to cut a small piece off from the cube and let it unthaw in a small cup filled with tank water, stirr it around and once its all free floating you pour it in and watch him go crazy for it.