You keepers must have come up with some way to mark which frog is which in your enclosures. Unfortunately, they can look almost exactly alike if they are not heavily marked!

This would simplify record-keeping a lot. For example, keeping track of which are males after the nuptial pads fade.

OBVIOUSLY you cannot use permanent pen or anything else that they could absorb into the skin, and I don't see frogs accepting any kind of ID band.

Is this even possible, and has anyone figured it out?