Found a jumping spider! Need help identifying species and gender if possible as well as care!

I was tending to my jumping spiders yesterday when I noticed this little guy lurking around their enclosures… they’re fairly tiny (I’m a small woman and have my hand against the enclosure for reference) but not small enough to accidentally sneak in however I did move him to a temp old enclosure we’ve been using for our temp residents that we’d house for a day or two, feed, & release when the weather was decent. Considering it’s now the dead of winter with no warm days in sight, I don’t mind keeping him for a few months until spring or for the remainder of their life if they’re mature. That being said, I need help identifying what they are and if anyone has suggestions for food sites please drop them below. All of my spiders are adult bolds so all I have on hand are spikes which are way too large. I’m guessing fruit flies would be the best choice?