Angelfish internel bleeding(?)

[Now3]

Hello everyone, I own a solo blushing angel in a tank by itself. Was in a 40 but now in a 20 since I had to take the 40 down. Tank is densely planted and has 1kg of fluval biomax media and mechanical filtration with purigen in a 265gph canister.

High light, co2, and dosing. Ammonia and nitrite are 0, nitrate below 5pp.

Please let me know what the problem is here, thanks.

 

[Andy Sager]

Possibly too much CO2. Blushings are not always the easiest to diagnose for disease because under normal conditions, they can expose things on their insides. I would start with cutting back on the CO2 and if the bleeding does not decrease ( or starts to increase), you have to consider internal disease.
Hope this helps.

 

[fishwonder]

I have no idea but maybe this information will help.
https://aquariumscience.org/index.php/11-11-red-skin-blotches/