FIrst off, not everyone here is a master or expert. So dont always take their advice, cause some give out bad advice. Second, for the tank size I dont think its bad. Add a bunch of hiding spaces for the BGK and the catfish. The tank is pretty roomy for 1 Oscar and 2 Angels. Ive seen a setup with an Oscar and Angel. All I am saying is keep and eye on it. And for those saying the Mega will get too big, its not gonna reach 24 inches overnight. People here grow out fish that are way too big for their tanks all the time. Dont be a hypocrite.
All I am saying is be responsible and do the right thing if a fish outgrows its tank or if fish are being bullied.