Axolotl Pigment Changes... and Sick Axie?

[Asevernnnn]

1) Okay so, I have 2 Axolotls, One lucy piebald, and a gfp wild.
During the day their color/pigment is all normal and dark. Then at night, the pigment changes a little bit:

~Piebald Axie: Spots are lighter than usual
~Gfp Wild: No longer looks like a wild type but just a very pale green axolotl.

Is this normal or should i be concerned? The piebald one seems fine but, the wild... And its not just different lighting.

2) The piebald has eaten 3/4 of his legs. Its not the first time its happened. Hes in a hospital tank now, looking pale(as mentioned above, but a little paler than usual). But he is refusing to eat. And seems very afraid of anything moving near him. His legs are regenerating slower than usual and are short little nubs right now. Hes fairly thin but not starving thin. I tried giving a wax worm and he refused it. Any treatments or what to do will be well appreciated.



*I use the 'Stress Coat' Dechlorinator that everyone recommends for axies.*

 

[sabre]

Have you checked your water parameters in the tanks (preferably with a liquid test kit)?

Sorry if this is blunt, but if the piebald has a habit of eating the wild type's legs...why do they still share a tank? Or at least a tank without a divider?

I could be wrong, but don't axies get pale when under stress? It seems odd to me that their colors would get lighter at night and not darker. Do you flip a light on at night to see them or something? Just thinking out loud.

Also, what do you normally feed your axies? I'm assuming the wax worm is an attempt to entice him with a treat and not a staple.