Red mark on gill cover and white mark

[Cardeater]

Have you tested your water?

Yes

If yes, what is your ammonia?

0

If yes, what is your nitrite?

0

If yes, what is your nitrate?

Less than ten

If I did not test my water...

...I recognize that I will likely be asked to do a test, and that water tests are critical for solving freshwater health problems.

Do you do water changes?

Yes

What percentage of water do you change?

71-80%

How frequently do you change your water?

Every week

If I do not change my water...

...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.

Could this be a bacterial infection? I have a thread here that seems to not generate any responses so I wanted to create a separate thread for this fish.

I think I'm moving her out. I have another fish that's been isolated that has been doing salt treatment but no kanaplex or Jungle Fungus Clear yet so I guess she'll go in there vs the other QT tank that just finished 3 kanaplex treatments.

I've kept her here with the white mark for over a week now and she's the only fish in main tank that I'm worried about currently so better to isolate her.

She's like 5.5 years old like the male millenniums I've lost recently so could be nearing the end of her life span.

 

[Cardeater]

Yeah she's got something bad going on there. I can see it clearly now that I caught her.

 

[kno4te]

Looks like a puncture or from where a parasite could’ve dug in. Would dab the area with methylene blue if you have any. Don’t get any behind the gill plate. Owtherise quarantine with some salt, clean water and good food.

 

[Cardeater]

Looks like a puncture or from where a parasite could’ve dug in. Would dab the area with methylene blue if you have any. Don’t get any behind the gill plate. Owtherise quarantine with some salt, clean water and good food.

It's in QT with another fish from the same tank that I removed two weeks ago.

I got an interesting response on another forum as a possible explanation for what I'm experiencing.

Red blood marks on gills and white marks

I just took this female Millennium out. She had a possibly concerning white mark that can see in these pics from last week but when I saw this today I took her out. I had seen it before but it went away but now it's back. I'm going to have to put her in with this fish that's already in QT. Had wh...

forum.aquariumcoop.com

Poster said the obvious that I can't be sure without examination but could be Mycobacteriosis bc rainbows are suseptible to it.

I have two other rainbows that look like they may have marks but I know I am paranoid now so didn't take them out yet.