A few years ago I had a baby I got at about an inch, kept in a 40B. Once it hit around 4" it seemed like it grew about an inch a week until it hit 8" or 9" and slowed back down a little. I was able to keep it in the 40B for almost a year before it outgrew it, so you should be able to get at about 2 years out of the 225.
(mine went to a 240 after the 40B, then eventually to a 6' x 8' indoor pond)