Good call. I have had a GT for almost 2 years, and that little bugger is the slowest grower out of any fish that I have had. That O will jump on you with growth, they are spurty better move him quick!
Yeah, a GT doesn't grow very fast. The one I have now has maybe grown half an inch in the last six months. Sometimes people seem to think every fish grows as fast as an Oscar. A GT would be fine in the 25 for a while.