Gray Treefrog tadpoles turning transparent?

[ligreys]

I have 5 hyla versicolor tadpoles in a 1 gallon critter keeper filled to the top with water, a bubble filter, some aquarium gravel and rocks. Within a week and ahalf they have tripled in size, and are constantly foraging for food (feeding them tetra tropical food and HBH tadpole bites) They appear to be healthy, growing proportionally, swimming well and growing fast. They get a water change/bottom vacuum about every 2 days. The tank is near a window ~4 feet away, gets a decent amount of ambient light and 1-2 hours of fairly direct sunlight in the late afternoon.

My question is that the past few days their color has gone from black, to black and gold like spots, to light tan. And at night with no light they become as close to fully transparent as possible (i can see through the forward part of their head, and all of their organs) Is this normal?

I know hyla versicolor change their color but its just seems weird for them to be getting this transparent

[Pluke]

I think I remember seeing tiny gray tree froglets freshly morphed from tadpoles and them being somewhat transparent, I'm pretty sure this is normal. I'm sure someone who knows more on the subject while dime in. There are probably a few people here who have raised them, in fact I know there is.

[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