They are tiny little bugs that live in the soil. Teeny little bugs that keep a natural ecosystem healthy. You'll often see them in your potted plants when you water.

I got mine from joshs frogs. There are 2 types and you want the tropical ones. As long as they are put into a tropical moist substrate, they live and reproduce, and keep everything clean.

Many dart frog people colonize their vivs with them because the froglets will eat them and they keep you from needing to change out substrate.