Please don't take this as being cruel or anything. I just feel that in my 20+ years of fishkeeping that a 200+ gallon tank is just plain nuts for housing one fish!? I've had Jags, Devils, Salvinis, Convicts, even a Flowerhorn. I too have had multiple tanks going at once and still do, I just feel a 90 g. is good enough for a 9" Dovii for now, maybe a 120 when full 20" tank raised grown. If he gets bigger than that?? I'll deal with it how I see fit.