It's more of a case that they nip compared to others livebearers. Paradise gouramis will obviously eat smaller tankmates if they fit their mouths.I have 300+ in my 1100gal pond. They all came from 4. Almost 8 years ago, I'd say.
I never knew about their aggression, as the only fish they're in with are 14-16"+ koi. Are they so aggressive that they would kill blue paradise gouramis? I put a pair in, and they disappeared quite quickly...