Gray Treefrog tadpoles turning transparent?

[Pactolus]

Tadpoles and young froglets change color at night and become lighter colored. I'm not sure why it happens, but it happened when mine was a tadpole and it still happens now a few weeks after he morphed.

[ligreys]

ok. I figured it was normal since they appear healthy in every other respect and the water perameters are near perfect. Just wanted to make sure it wasnt a sign of poor nutrition or anything

thanks