Lol, if it's properly maintained in the 10 gallon, it can hit 4" without stunting at all. My Jag went to 5" in my 10 gallon and he wasn't stunted. I did 50% water changes daily and fed him like crazy and he grew to that size from 1.5" in less than 3 months. Then he was moved to a larger set up and almost killed my other fish in there so I sold him. But the key to fast growth would be water changes. Continuous water changes, the more new water that goes in each day, the faster the growth. =) I want to set up an auto water changer that runs 24/7. New water always coming in and old water always going out. But yeah, don't feed that jd anything like worms and stuff. It might get bloat. XP