Do axolotls eat less in colder water or during breeding season?

[Sylerwin]

My folks are caring for my axolotls while I'm away at school and aren't the best at describing issues so bare with me:

My parents have been telling me that my axolotls are basically "taking turns" at not eating. They basically fast themselves for a few weeks before randomly eating again.
My mom is worried about this one though. She says it's been two weeks and she said that yesterday he was "floating" and that now he has a "hump" in his back. She said that his gills are brown (he's a dirty lucy), so not sure if it's his typical color just changing.

My mother is horrible at photos and nor can she simply describe what they look like. She sent me photos of him and it appears that he has spots on his side. he never used to, so again I can't tell if it's just the regular spots changing or if it's sepsis.

Water tests are coming back normal, my dad says he's doing water changes just like I taught him with the dechlorinator....
Any ideas?
I'm going to try and walk her through taking better photos

 

[Sylerwin]

My parents picked up a pellet diet from the breeder they met after explaining that he's not eating the earthworms. It has "pressure extruded" earthworms, bloodworms, blackworms, spirulina, soybean meal... no fillers or byproducts. Going to have them try feeding that

 

[sde]

They do slow their eating, and don't lose the weight they gained from eating as fast. Their metabolism slows down. The temps in my shed is low enough that I don't have to feed my newts more than once a week.