I tried feeding my oscar Hikari Gold and all it did was stink up my house...it supposedly is "the best" pellet food...whatever. I since have been feeding my oscar HBH Oscar Show. Unbelievable. Its like crack for fish.
I also feed it earth worms, nitecrawlers(yes, the 6"-8" ones I get at a bait shop), June bugs, grasshoppers(green ones with legs, brown ones no legs),the occasional cricket when I can find them...they are out at nite.
What I dont feed...feeders. Goldfish, guppies etc. I have tried fruits and veggies, kind of hit and miss but spinach and seaweed(dried form sheet) Oscar likes it...occasionally.