I picture glass frogs sitting camouflaged in green vegetation, but the ones we saw in Panama were all perched on streamside boulders.

This one was also perched on a boulder, though at the edge of a decorative pond instead of at the edge of a stream. It then hopped onto some vegetation, so at last I got the green-on-green look I had expected in a glass frog. (To be fair, we did see a few others, and they were already in the green vegetation.)