he could more than likely fit them in his mouth, he is like 7-8 inches long. would they be able to outrun him or not? i have put small goldfish in for him and he almost couldnt catch them... i wouldnt feed him feeders, but sometime poeple win goldfish from carnivals or what ever and ask me to take care of them for them... and i just tell them next time i see them that they died. has anyone kept tiger barbs with oscars before??