Our arrowana was in a 220 gal tank with our two dinner size pacu's..everyone got along well.. the problem is if a fish should get playful or swim in excess the arrowana gets nervous..we lost our 2 ft Arrowana because he jumped out of the tank.. we have a new Silver Arrowana now and a pleco and cat fish is all we added to his tank..arrowana's i find are just too jittery for anything but very calm tankmates..