Small worms

[John]

Could be from the frog but sounds a bit big. There are plenty of nematodes that live in soil that would fit that description too.

[1beataway]

I did see one that was about half an inch long on one of the frogs, but it quickly disappeared. It was still just as thin.

Think it's dangerous?

[Kurt]

I would just thoroughly clean the cage and have the frog treated for parasites to be on the safe-side.