12oz or 16oz is plenty. try to make it easy for the shrimp to climb in, place against a rock or something. I place the bottle where it will remain steady even with normal flow also usually placing another rock on it so it stays put. After that, I use a baster to inject a fairly heavy amount of reef roids inside the bottle. (1/2 teaspoon of roids mixed with tank water nearly in paste form, not liquid, you want it to sink down in the bottle) Do this with the last bit of light and you'll have the peppermint by midnight. You can try mysis or any meaty seafood but the roids works fast the first time.