I have been making and adjusting my own fish diets for years. You have to keep in mind what % you want/need. Are you feeding for growth, breeding, color, etc? I would strongly encourage adding a dillouhted garlic extract this is to encourage fish to eat it, and hard to feed fish. And a stabilized vitamin C or citric acid. It doesn't take much of either. But has profound results.
I use dry baby cerial as a binder, and then freeze. Gelatin works well, but can make melty oozy stuff behind or maybe I used too much gelatin and not enough of the other stuff.
I use spinach, a variety of other leafy greans, worms, shrimp, etc.
I have even tried using dog food, and live pinkies.
Grow out rations and breeder rations require higher protein than finisher and maintenace ration. I haven't had much luck with extruding or pelletizing. Look into small hammer mill if that's the direction you want to go. Freezing is cheaper though.