I have a 4 year old 40 inch long male ball python. He hasn't eaten in 5 months and I am worried he might be sick. He is acting normally otherwise and all his accommodations are met and nothing had changed before he stopped eating or after. I feed him pre-killed and I've tried some tricks here and there like braining or rubbing gerbil litter on the rodent. He will inspect the food, but won't eat. I usually leave it with him over night as he usually likes eating alone in the dark better.

Last night I offered him a live rat and waited for about 15 minutes. He showed the same amount of interest, but did not eat it or try to attack it. I weighed him today and he is at 1700 grams. I'm not sure if he has lost weight or not, and if so, is he in normal range for a ball python of his length?

Is it time to take him to the vet?

Thanks.