If they are baby crickets, they will die off in a couple weeks without food. If you are worried or they are bothering your frogs, do a substrate change as Lynn has noted. Baby crickets look just like adult crickets but are tiny. It is likely that a big mama cricket was carrying eggs, ready to deposit into your nice, warm, moist substrate. Grrr!

This happened some time ago in my pacman's tank. They did annoy him so I took out the substrate. Rinsed until they drowned. Cleaned them out and placed new.

Good as new .