well whats nice with the gelatin is instead of freezing it, you pour it in a tray and put in the fridge. Then you can cut out cubes or crumble it to make different size pieces for all your fish no matter what size. When you are feeding fish that vary in size from top minnows to amberjack this is a nice thing
I've used clams, mussels, squid, crab, and herring in my mixes in the past, not all at the same time obviously.