Help with Shubunkin Problem

[El FARVA]

Shubunkin in 1 to 2 days tale turned red with part of lower body aswell.
What am I dealing with? Could it be color change, I think its to fast for that.
Or is it some disease Or injury?
Water at 0 Amo.Nitri.Nitra.
Water Ph 7.2

 

[El FARVA]

Photos

 

[FishGuest5123]

Oh, there is something terribly wrong. What are your water parameters and how often do you clean the tank? How big is the tank. Type of filter?

 

[El FARVA]

Amo. 0 Nitrites 0. Nitrates 0.
Ph 7.2
40 G.
Water change daily.
Filter clayton.
Have 3 small koi in tank they are perfectly fine.

 

[FishGuest5123]

How long have you had him. Do you have a lot of plants in your tank as it is very unusual to have 0 nitrates in a goldfish tank? Is your tank cycled? Are you aware of the aquarium nitrogen cycle? Could he have gotten caught in anything? I would continue daily water changes and add Aquarium salt at 1 tablespoon per every 5 gallons of water the first day. Be sure to dissolve the salt first in a little tank water before adding to keep it from burning the fish. Continue to do a 50% water change daily for 2 weeks and each time add 1/2 tablespoon more of of aquarium salt. If he hasn’t hurt himself internally, this should help. He’ll be fine with the salt for 2 weeks. Aquarium salt acts as an astringent for injuries and fights bacteria while also reducing stress. I breed goldfish so I know quite a bit about them. Keep us posted.

 

[El FARVA]

About a month.
No plants but do 50% Water changes daily.
Used media from already cycled tank 2+ years old to cycle.
Already using Aguarium salt.

Thank You for your help. Ill inform on progress.