I would say a 450gallon would be a good choice or at least some tank with dimensions of 6ftx3ftx2ft minimum(LxWxH). The pond idea is really the most affordable but if you do want a tank make sure its a behemoth because right now your really limiting the fish ability to turn and have swimming space, a good rule of thumb is at least 2-3 times the length of the fish for swimming space. ~Trent

