btw green terrors grow VERY FAST, jsut before xmas i got a green terror 1 " for 50 p lol at the lfs because they were fry, now he is 6" and its been a few months !!! hes frienldier because hes with large cichlids like my sig, a frontosa, 2 small oscars and a mbuna. hes getting on fine ijsut thought ishould warn you that they do grow very quikly given the right tank size tank mates and diet etc.
good luck with the oscar problem, mine were given t ome as sickly 1 inchers now they always following eachover around and i mhoping they will maybe turn out to be a pair, but if their not then its fine, i think you should get your oscar a litle friend, oscars are very sociable, ive never known anyone who doesnt keep them in a pair or trio.