my baby jag looks just like that and its about the same size to, but he is a little more fat, because he is in a tank with about 40 yellow lab fry for grow out. every couple days i find a half eatin fry.
Bingo. I remember I got my jag from petsmart at about an inch, and threw him in my tank. He was always being cornered and just hid, thought the tankmates eventually just ate him. A year later, and doubling the same tankmates, he's the king of the tank! Good luck with it.