He's still young so not yet really. The female firemouth is the most "moody" fish in the tank. The Oscar (Hours) will slowly swim towards the angel or firemouth if they get too colse but they get the message. The main problem is keeping the oscar and mbu seperate when feeding. The Oscar has a few nasty scars on his mouth where he has tried to get food from inside his jaws, I'm hoping he will learn its a bad iea soon. I've never seen a fish with a better temperament than the mbu though.