Koi losing scales... help?

[Fishlover222]

My koi is approximately 5 years old and is losing scales, it also has a cut by its back tail fin.

is this normal? What could be causing this?

thanks I’m advance

 

[Fishlover222]

Another picture of it

 

[j.w]

@Fishlover222
Maybe it is scraping itself on something due to parasites? Really I have no clue. I see also it has some kind of ulcer or sore of some kind. Could it be due to spawning? They can get pretty wild sometimes.

 

[Mmathis]

Hello and welcome! Pretty fish!

Give us some information about your pond. How big is it? How many fish and how big are they? Filtration you use? Water test results (actual numbers, not “normal,” or “OK”)? Any changes you have recently made (new fish added, etc.)? Do you use any chemicals? Natural predators (herons, other critters)?

 

[Nevermore44]

That looks like doitsu koi (partially scaleless).... so i think the only problem is the red areas that need addressed per Mmathis

 

[Tula]

What @Nevermore44 said.....no problem with the scales. The problem is the red area.