Yes you can, to treat with paraguard however, best to QT the fish n treat with paraguard. Not much articles and definite answers on whether or not the paraguard is reef / invert safe.. If you observe the fish to have brookynella best to qt the other fishes as well. Then wait for the tank to be fishless for 3 to 6 weeks before the tank should be cleared of brooks I'm still new to the hobbie so if im wrong, someone please help n advise accordingly Sent from Singapore Reef Club mobile app