So, he has only been in the tank for two days?
If so, I would give him some more time to get used to the tank, try to feed him every day until he finally does. Just curious, what are you trying to feed him?
Sounds strange if you have had him that long, and now not have him eat... lol, I don't know, I would just continue to attempt to feed him every day until you get some results. Other than that, I'm at a loss for words, lol.