are you feeding him in his eclosure? he may not feel secure.

my girl was "trained" to eat in a seperate container from the one she lives in ( her substate could be eaten and cause problems which is why i feed her in a different container ). if i've EVER had issues getting her to eat (shes on F/T ) its either because

1. the rodent is not warm enough

or

2. she dosent feel secure enough. i feed her in the bathroom (no carpet ) and put the rat in, close the lid on her feeding container, turn the lights off and close the door. she always takes them for me.

you could try covering 3 sides of the tank with dark paper, to help him feel more secure. i'd also highly suggest getting a fecal float done.

also, i've heard it is advised against to feed gerbils, hampsters and chicks.no gerbils because they're expensive and difficult to find and balls can imprint on them, meaning if you start feeding them it will be VERY difficult to switch them to something else which if you ever need to get rid of your animal, could make it very difficult. no hampsters because they're high in fat (?) and no chicks because they arent very nutritional for balls and they can cause their stools to be very runny. again, this is all hearsay, i wouldnt quote this directly. but i'd definately do some research before switching the prey item.

good luck with him!