Puffers are hogs...while a dogface only gets about 8-10" as an adult, it still needs a specialized diet of crustaceans to keep it's "Beak" whittled down. They also are scaleless and can be prone to disease in small setups. The tank size is to help dissipate the waste from their eating. While you could feasibly house one in a 55 gallon, it would be a nightmare in maintenance and could be the only fish. They are also highly predatory and may nip at other fish. Generally a puffer grows fairly slow, but it's all about water chemistry and how much you feed them...they are big time beggers...like a underwater Labrador. I wouldn't advise getting it to house in a 29 gallon AT ALL...a 47 gallon column isn't really a good fit either...they need space to entertain themselves. I would say a minimum in a single specimen setting is 75-90 gallon...it's better to let them grow into the tank then to move them around...they don't travel/ship all that well.