This looks like what my newt has got. I've heard it called "the shine", the most common symptoms are irregular shiny skin and exaggerated hip and spine bones. I don't think your newt is very thin, I think he's got the shine. I agree with Chinadog that shiny skin is a sign that something is wrong. I've also heard that head sores and something that looks similar to hiccuping are symptoms as well. If I'm right, then the best course of action is to put him in a terrestrial setup where his skin is allowed to dry a bit. Cool temperatures help as well, and keep on feeding him. Hope that helps.
My axie is acting woerd he was a rescue as stated in a different post he got better and now seems to be deteriorating again...again all tank conditions are OK and as should be. He seems to have some black dapple like pattern under his bottom lip? Is that normal? And his two back feet have a little wierd growth? Almost? Tiny tiny tiny lump. His capillaries in his feathers also appear darker and more visible. Any help would be appreciated