Hi, I have a 12-year-old comet goldfish who has been having some issues with his swim bladder, to the point that his spine is somewhat curved. He has lived in a 5-gallon tank for most of his life, and I would really like to buy a much larger tank for him. At this age, if he were to live in a larger tank, would he grow more? He is about 4 inches long now. And if he were to grow, would that make his spine worse? I know that in humans with scoliosis, growth can make the condition worse. Is the same true for goldfish? Also, what size tank do you recommend? Thank you for all of your help in advance.