Ive had expirience with all of the mentioned above and the ornatums are very aggressive to conspecific and other large cichlids that pose a threat. the snooks ive had try to push other cichlids around but quickly submits lol the festaes will run their tank or at least try to. So i would put the ornatum back into the 265 with the snooks. the snooks have been in there for about a week now so they should be settled in and by placing the ornaum back in he'll have to get re-adjusted and acquainted he'll chase the snook a litte bit to establish dominance and the snooks will get out of his way fairly quickly. and in the mean time you can decide on a price to sell the Ornatum and possibly sit on him till you get the price you ask for The snooks are more open water swimmers and are faster than the Ornatum and maybe give the Ornatum a lil place to call his own and they should all be fine bro