Pearlscale goldfish bruised & fraying fins after aggression from moor

ILL PEARLSCALE GOLDFISH - please help!

I recently had to separate my black moor and Pearlscale goldfish as the moor was being aggressive and pushing him into the ornaments. I had to do this once before as he had a lot of bruising but after being separated for a while they completely went away. When I tried to reintroduce them, the same thing happened. He was only in the tank for a day before I removed him again.
My Pearlscale now has similar bruising as last time but he has also developed frayed fins at the back and one of his small fins on his bottom is now very red and looks like it is quite stiff/doesn’t move as well.
Could anyone please give me any advice as to whether these things will be due to the bullying (and therefore if they will resolve themselves like last time) or could it be some kind of disease where I need to intervene?
I have tested and cleaned my water and all the levels seem fine (I was having a few issues with high nitrates over the last couple of weeks but they are okay now). I have attached a photo(the best I could get as he likes to hide!), so you can sort of see the frayed fins and dark red fin at the back and the bruising.
Thank you!!!

 

How big is your tank? What are your water parameters? There are a lot of factors that can cause aggression.

 

How big is your tank? What are your water parameters? There are a lot of factors that can cause aggression.

Hi, my tank is 28L which is now only housing 1 Pearlscale. My nitrates and nitrites are both 0mg/l, the pH is around 6.8 and the chlorine is 0mg/l. Do you think the fraying and red fins are caused by the aggression/bullying or something else?

 

28 gallon long or 28 liters? My guess is a lack of space is causing the moor to bully the pearl scale which is causing the fraying.

 

Hello, in regards to the aggression and bullying it is hard to say, but it could be likely that 28L (~7.3G) is horrendously small of a tank for even the goldfish alone.

I can’t speak much about the black moor, but goldfish require at bare minimum 75L (~20G) to live in alone, and even then it is still recommended to have at least ~115L for your little goldfish friend to have a happy, healthy life. If you can’t get a adequately sized tank I’d have suggest rehoming it (as it will face some very serious health implications in the near future) and adopting fish more suitable for the small space.

 

28 gallon long or 28 liters? My guess is a lack of space is causing the moor to bully the pearl scale which is causing the fraying.

It is 28 litres. Okay thank you! Should the fraying on his fins and redness repair itself with no added treatment or is there anything I need to do to help?

 

It is 28 litres. Okay thank you! Should the fraying on his fins and redness repair itself with no added treatment or is there anything I need to do to help?

As long as the water is clean and everything, the fins should grow back on their own. You might want to add some salt if you notice any signs of infection, but there's not much else you can do about it. Goldfish produce a lot of waste and since your tank is so small you way want to do more frequent water changes so that its always clean, yknow? I hope i could help

 

I'd like to add that getting a bigger tank is 100% necessary. You can keep him in there until the new tank is cycled but the sooner they're in a proper environment the better.