Sudden death 😭 baby jumping spider

[MissSpider]

My friend bought a jumping spider. It has gone through 3 molts so far. Just saw it yesterday and it was doing just fine. It was eating well, had water, a very nice vivarium Last night it went to the bottom of the enclosure an this morning it was dead There are little weird mites all over it that I've never seen before. My friend says their grain mights but idk. Can anyone help figure out what happened?

 

[The Snark]

Mites. Red or brown, predatorial, some species are capable of quickly killing small spiders - they pack a neurotoxic saliva. Gray white, grain mites - harmless. Assume predatorial. Grain mites don't attach to animals except by usually a rare accident.
Mites are hardier than any animal likely to be kept so a complete clean out and wash of the enclosure is in order unless another culprit is identified.

 

[MissSpider]

Mites. Red or brown, predatorial, some species are capable of quickly killing small spiders - they pack a neurotoxic saliva. Gray white, grain mites - harmless. Assume predatorial. Grain mites don't attach to animals except by usually a rare accident.
Mites are hardier than any animal likely to be kept so a complete clean out and wash of the enclosure is in order unless another culprit is identified.

Thank you for the info. I had a feeling My friend said she boiled everything before set up so now were just trying to figure out where they came from or how. It was so sudden

 

[The Snark]

so now were just trying to figure out where they came from or how. It was so sudden

If thoroughly cleaned, probably came with the spider. One viable mite can equal 200-300 in about 3 weeks. Which can become >5000 in a couple of months. It's been an extreme year for mites. As example, 10 or more states have reported human infestations of pyemotes (itch) mites which have normally been restricted to Kansas, Missouri and Nebraska.

 

[Poonjab]

Mites didn’t kill that spider. Once a spider, tarantula or other animal for that matter dies, mites seem to appear out of thin air and begin to feed on the remains. To me personally, those don’t appear to be predatory mites. Just common scavenger mites. For all we know, your spider could’ve died from old age. Who knows. But I guarantee you mites weren’t the culprit.