there is a lfs by me that has a 13 year old wc dovii in a 120 square and the fish has maxed out at about 15" so its shorter than a dovii should be at that age. i would imagine in a 55 it would have the curved spine like most of the jds and be very unhealthy cause keeping water quality good enough will be borderline impossible. no dovii at all. if hes getting a 55 tell him to get a grammodes as they are like mini doviis and wont outgrow a 55