Advice appreciated, juvenile refusing food

[frogmin]

I have recently gotten 3 juvenile marbled newts. About 5 or 6 months old. Two are eating great but one hasn't eaten since they've been with me. It was night number 9 tonight. They were brought to me by courier so I'm unsure exactly when they last would have been fed before the got to me. The one refusing food is noticeably much thinner than the other two, though still just as active. I know it is normal for animals to refuse food in a new environment, but it's their size particularly that's worrying me, and I have never had an animal refuse food for this long before, new or otherwise.

My question is, at what point do I head to the vet? I don't want to be over dramatic (especially considering how hard its been to find a vet that will take non emergencies in the current situation) but I also don't want to leave it too late.

Some extra info: the two who are eating are eating small crickets, buffalo worms and earthworms. I offer food every night either via tong feeding in their enclosure or feeding them in a separate tub when giving smaller, faster prey like the crickets and buffalo worms (which is working well for those two that eat, I know some people suggest against this but it works for us and was actually the first way I got them to eat) I also keep a dish of buffalo worms in their tank at all times, and though I try to make sure they know they're there, no one has ever eaten from the dish or seemed interested in doing so. I am still keeping it there just in case, for the little one particularly. I try for a long while every night with her trying to entice her but she isnt interested. I believe I caught her shedding last night, if that matters?

Thanks

 

[AuSu]

Hi!
I have only firebelly newts and not familiar with marbled but I think with babies there might be some similarities. Could you offer smooth, living food like fruit flies in their environment? Buffalo worms sound a bit hard if these newts aren't used to them. Small earthworms vould work better. Also wondering could it be stressed when handling (to the feedin container) and refusing to eat because of that? I suggest something easy (not hard shell, not biting) to eat as a leave-on so the tiny one could choose when & how much to eat! And since this answer comes long time after your original post, I hope the situation is already better!