Brick has never stopped being an Oscar. Two things will set him off without fail: being openly challenged and being crowded. He doesn't have to be alone in a tank but he's no pushover either. I'd say he falls in the tolerant category. As long as other fish stay in their 'place' he's good. He's also been known to go after fish and block their hides. Only exception is the parrot Boss who even headbutts the Oscar occasionally.
Three months ago I stopped a potential situation with Brick and syno Spot. Just happened to go past the fish room in time to see Brick's mouth firmly clamped over Spot's head. Before I could move he spat him out. Could have been a warning. Synos are known for nesting behavior especially during water changes and Brick hates fish bumping and squeezing under him. Spot tried to 'clean' him a few times and got slammed into the glass. Can't say synos are the brightest bulbs.
View attachment 1527282