Very sorry to hear about your snake. What I wondered, when reading your post...was if you took it in to the vet at any time during its extended fasting period to search for a reason it may be fasting. (ie: parasites or other internal infection)


Assuming all your husbandry has been correct throughout the life of the snake, and assuming it did, indeed die of some "internal infection"....then my point of view is this: The seller might be partially responsible if they knowingly sent you a sick animal...but you, as its current keeper are far more responsible for getting proper veterinary treatment before it was too late. Over a nine month span of fasting, for a young snake that should be eating well and was obviously losing more weight than is healthy...I would have been to the vet multiple times for complete checks of fecal swabs, blood tests, and whatever else they could have looked for.

Failing that, I see no hint of responsibility falling back to the original seller. Also, if you DID take it to a vet and the vet could find nothing wrong with it...then how would the original seller know it was sick either? It obviously had been eating well at some point to have reached 690g of weight.

Anyhow, that's my answer to your question about where my thoughts lie on why the snake may have died. I truly am sorry for your loss...and if its not too late, I concur with the other gentlemen who suggested a necropsy.