Sorry for double posts. Its a side effect of doing water changes while posting.
What I meant was current sizes. My first concern would be that no one ends up on the menu. The second is that the paroon shark can get up to 8 feet (although I'm gonna guess this takes a while ). If no one fits in each others mouths, and you know what your going to do once the paroon starts to looks like an overweight adult sunbathing in a kiddie pool, then I personally think you'd be okay for a while.