So far as I can tell no one has adults, except maybe the early broods from the origional hatcheries. Mine is currently 13-14" after a short 5 1/2 months. So growth is comparible to young RTC, but as for it's eventual size we won't know for a few years yet unless someone comes on here with hard evidence of an adult, but to answer your question I would think it would be ok for 2 years in a 180 gal. Hope this helps. Bump for great prices and great fish. Chaca is tempting.