One Of Axolotl's tail keeps curling

[GabbyGums]

Hi! Its me again, I replaced the test strips n stuff getting a whole Water kit(just ran out today but ordered some recently) But Ive noticed one of my axolotls keeps having red veins(in tail) and a tail curled almost for a few days now and yet no other Axolotl(I have 4 now in same tank) has it and there's no other axolotl in the tank with an tail curled and no red veins in tail so mainly its one thats doing it. How frequent of Changes? I do water cycle changes every Weekend on a Sunday. How frequent of Tank cleaning? Every two weeks and on a Sunday. Last test results? I got no sign of ammonia, nitrates, etc which makes me worried that this could be injury but I see no injury or fungus sign. The Axolotl in question: His name is Butters, He's an Golden Albino whose an year old currently. His tankmates? Jelly, an wild type, whose an year old. Behind the border has two babies: Peanut, an mosaic, and Cucumber, an enigma. Its been a couple of months of having the babies. How did I get all four? Jelly I got at a Petstore, Butters I got at Axolotl Planet, Peanut at Ivy's Axolotls, and Cucumber an accidental birth from Jelly & Butters so now I have 53 baby axolotls in total(we just had a break out in nitrates in their end, which made us always check their test results to the point we've ran out.) Any other Tankmates: Nitrate Snails(two of them.) They help with the Algae problem in the last tank.

 

[wolfen]

if the tank is cycled and of the appropriate size then a water change only needs to be done once a week.
because some axolotls are better at adapting to habitats then others some will show signs of stress over the smallest issue whilst others are fine.
might be an idea to monitor butters to see where he resides, whether he is trying to dig etc... as this may give clues as to what is causing stress.

 

[GabbyGums]

if the tank is cycled and of the appropriate size then a water change only needs to be done once a week.
because some axolotls are better at adapting to habitats then others some will show signs of stress over the smallest issue whilst others are fine.
might be an idea to monitor butters to see where he resides, whether he is trying to dig etc... as this may give clues as to what is causing stress.

Well thats what I'm doing with the tank overall weekly, Its an 40(replacing it soon, I just ordered a new tank) soon to be 50 tank with plants and many structures. He has been digging in an specific area where the plants have been ever since Ive gotten him but the stress just showed pretty recently and idk whats causing it

 

[wolfen]

before you do a water change go through the substrate (in particular near the plants) with a fork to release any trapped muck/debris/gas and to aerate it , as it could be that he has had a face full of bad substrate which is stressing him.