What are those ?

springtails! nematoads will knock them down if you want or BTi, they won't hurt anything but some people just don't like them. I had them in my one grow, I used nematoads on them and did not see them again. Good Luck!

Absolutely fascinating... in a kind of "ick!!!" way... Did a little research and yeah, they don't do a lot of harm although SOME species will feast on roots - god knows what species that is or how you would distinguish! I DID find this little nugget though (and if this were MY grow, I'd definitely just want them out of there!): "If springtails find it an attractive home, there's a good chance you've been over-watering your plant in the first place. Allow the soil to dry out completely, then sprinkle diatomaceous earth on the soil surface. This combination should kill off the insects." This is from https://www.google.com/search?client=firefox-b-1-d&sxsrf=ALiCzsZAqh4zEgBqlhEKrhuDFAh0FiZeLA:1657807338388&q=Does+diatomaceous+earth+kill+springtails&sa=X&ved=2ahUKEwj_v4rMxfj4AhUBjYkEHXYuAcgQ1QJ6BAg_EAE&biw=1440&bih=762&dpr=2 Good - ick! - Luck - ick!!!!!

Looks like spring tails I believe they are called. They eat decaying matter. I don't believe they are harmful. Just jumpy. Lol.

springtails

I would like to know too!