Every couple of months I'll make up a batch of dried flake for my shrimp and plant eating fish. The exact components vary according to what's on hand or readily available at the time but the basics are pretty simple:
Dark leafy greens: kale, spinach, turnip and radish are the ones I use the most -radish especially as I always have a bunch on hand-but if it's leafy and in my fridge, it's fair game. Celery leaves went over big time, though I seldom have 'em on hand and it's not unusual for a bit of wilted parsley to end up in the mix.
Greens are blanched, chopped into a fine mash then mixed with:
A pinch of the powdery remains of any of my regular fish foods. Dehydrated blood worms and shrimp tend to have a lot of waste powder in the bottom of the container and whenever I get down to the last crumbs I dump the remains into a container set aside for them.
A pinch of nori--dried seaweed that I keep on hand for Japanese dishes.
The mess is spread out thin on an old chopping board to dry, the resulting sheets are broken up and keep perfectly well in an open dish by the tanks. To feed, I'll pull the amount I want out, toss it in a cup with a bit of tank water to rehydrate, then distribute to the various tanks once it's wet enough to sink to the bottom.
Note: I don't use any gels or binders. If the mix is chopped very fine and dried in thick mats, it'll often hold together reasonably well on re-wetting, but most of the time I do a thinner mix and just accept that it'll be messy in the tank. The shrimp and fish don't mind in the least and I find it leads to more equitable feeding as the fish shrimp and snails don't end up fighting over one spot of food. I just have to be careful not to overfeed as there's no concentrated lump to remove.