The Jello Bean Method
Pick out an assortment of seafood, the more varied the better, the seafood medley is a great way to go for a starter, 1 or 2 of the components (mussels and clams I think) are cooked but that is no big deal, the squid, octopus, cuttlefish etc are raw, try for small whole fish of some sort(guts, bones, and all) for max nutrition, most fish markets have smelt in the freezer, and any thing else that looks interesting. Munch them up to the appropriate particle size, I prefer a food processor, you can use a blender if you do small batches and add enough liquid to get uniform particles, you don't want mush. Throw it all in a large wire mesh strainer and rinse throughly with tap water (you don't have to be anal and use RO, but if it makes you feel better go right ahead). The rinsing is key, there is plenty of vitamins and nutrition in the particles, the liquid will just add extra nitrates and phosphates, won't do your fish & inverts any good, most peoples will thaw and rinse frozen plankton etc to avoid this sort of thing, rinsing prior to freezing eliminates this step when you are ready to feed your critters. I don't bother with selcon on my glop because I think a lot of it goes into the water rather than your fishes guts, I do use Selcon but I put a few drops on the flake food I use, it soaks it up completely and I believe the fish get more and your tank is polluted less.. I don't use any veggies myself because I like to use nori separately, but that's just personal preference... I don't bother with vitamins, IMO not necessary with a varied diet, also the quality flake food ( I like Ocean Nutrition) I use has all the added vitamin stuff.
And now for the most important thing.....Get on eBay and do a search for Jell-O beans, use Jello without the dash also. You don't want the easter egg molds, look for the red Jell-O bean molds, there are usually 6 or 7 for sale, you can pick them up for less than $10.00 with shipping. Each mold has close to 100 individual jelly bean shaped molds, this works much better than the cocktail mini ice cube trays, a lot more convenient than busting up a flat sheet also, give more precise portion control to boot. Just spread the glop over the molds, freeze, pop them out and throw in a baggie and you are good to go.