[Snaky]

I would a vet take a look at the faeces of the new snake, just a small remark on the quarantaine part. For the rest I have nothing to add to the posts above. Cyrtopsis are also the most challenging species of my collection with regards to eating.

edit:
Saw past that one... little addition.

In my experience, garter don't need brumation to breed. Brumation helps to have a better result for good, healthy offspring, but no brumation will not make sure that they won't breed. I know garters that never brumated and still had good offspring.