Blood red tail

[Jhenni1103]

Good morning,
I have an established 6700 gallon Koi pond I have been blessed with never having a problem. I’m away helping a family member for two weeks. My husband states that one of the Koi fish tales is blood red. He sends me a picture. I did a little research And I had him add Pimafix then five days later I found the fish dead. I show signs of other fish with slight redness in their tails. I’ve never encountered this before my fish are raised from babies and they’re all about 16 inches without their tails. I did introduce three small fish one month ago if anybody could help, I would greatly appreciate it. I had 13 fish in there now and live in north Florida water test is perfect except alkalinity is 40-80 water temp is 54

 

[Jhenni1103]

Pictures attached please help

 

[Lisak1]

Oh that is not good. I'm going to guess your new fish introduced something into the water that is affecting the fish. That is obviously infection.

 

[mrsclem]

Hello- do you have a test kit? Red Ness in fins Canberra a sigh of high ammonia or nitrates.

 

[j.w]

@Jhenni1103