I always wanted to ask that myself, you always hear "don’t over or under feed", well how much right????
Robyn is right about variety & the peas etc for SBD. My Ryukin has a small case of SBD and peas do the trick.
Mine vary from: Peas (two chopped), cucumber (half a slice, chopped), pellets (about 10 for 3 fish), flakes (2 pinches), gel food (3 small cubes), bloodworm (pinch), daphnia (2 pinches), tubifex (1 cube split into 6 smaller pieces), adhesive tablets (1 stuck to glass), they weren’t too impressed with shrimp & krill!
They get flakes in the morning, and evening varies I mix and match, sort of like;
Night 1: pellets
Night 2: blood worm & daphnia
Night 3: green foods
Night 4: gel food
Night 6: tubifex
Night 7: adhesive tables & daphinia

don’t know if this helps at all???