well i had to remove my tern from my shoal and put him in a solitary 55 gal. for himself. he's just too mean. there's no such thing in a piranha, i know. he just was too antisocial and territorial and big and strong to risk him around my smaller p nats and p not and big piraya. don't get me wrong- i love him. he's totally brutal; but when i was in the room yesterday he must have fought every fish twice after starting with each one. that's it, i said. and he lost his shoal privliges. anyway, the rest of the shoal, five in all now, are getting along famously without the neighborhood bully. just to be me i added every fake plant i could find in my house to the pygo tank for a fun and low maint. jungle river effect. well, they love it and i have to say i do too. it'll probably only last until i vaccuum next but who cares? fake plants are easy to add and remove.