I didn't know that not fully submerging your ally snapper in water will cause it to be... well.. snappy. No wonder my lui lui is so lazy. She has so much water in her tank.

Is it the camera or is the snapper's tail green from algae growth?

More sunlight? Basking makes them more active. And basking helps them digest some vitamins. Move more, digest more, can eat more I guess.

Erm... Skin peeling of as in? If you see floating pieces of their skin in the water, yah that's normal. They shed skin as they grow bigger.

O.o How come not keen on eating? This is Malaysia, they don't go into hibernation. Do you let your turtles bask? Red ear sliders love to bask.