he'll come out. just give it time. It's easier for them to get food if they come out to the front of the tank, so even if the little guy is in the back right now, he'll eventually come out. I've got two that did that for about 2 weeks and then eventually came out to the front because it was the easiest way they could get food....... now mine swim around all the time and go back in the hole when they get tired of swimming...