Underfed or sick?

[Kaorte]

That should be plenty for a male. I'd see what the vet has to say.

You think so? I am guessing a 3 1/2 year old snake is anywhere from 800g-1500g normally. You think one f/t adult mouse is enough?

OP: I would for sure bump him up to two adult mice a week and see how that does him.

You could also get a kitchen gram scale to track his weight.