Just about any bug you are sure is pesticide free is good Oscar food. Tomato worms, earth worms, crickets, gypsie moths, lizards, roaches, rolly pollies, stink bugs, june bugs, meal worms, small fish, small cats, children under 1yr (unless being used for a tax write off) Expirement with the foods for your O's the more stuff you feed them while they are growing the better. Within reason of coarse, they aren't big on pizza but I had one that loved peperoni & sausage off of pizza. (as snacks only. The tank was in my room and when I was eating the O did too or I got wet, realy wet!!!!)
Things not good to try, bolagna, hot dogs, dog food, greasy meats cloud water and slime up the glass. Fish don't digest mamal fats very well so back off on them. And finally cotton candy like the number five is right out wrong!!!!