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Holes in fins (goldfish)

Subject: Holes in fins (goldfish)
by PH12345 on 19/10/2020 14:19:01

I have 2 goldfish in 200 litre tank. I also have Fluval 406 external filter. My tank is about 5 years old and established. I do water changes once a week but very rarely miss a week.
One of my goldfish had ick about a year ago. The other one seemed to be fine and had no spots. I treated the tank a few times and it worked.
Now, about a year later, the other fish has been starting to scratch aginst gravel sometimes and and dashing. It is also flickering it's fins sometimes. I can't see any spots on it's body. Sometimes he sits on the bottom next to a big rock but as soon as I go close it starts swimming around again, so I am unsure if it's a sign of distress or it's just resting because the current is weaker there.
What really worries me is that it keeps getting more and more pinholes on it's fins and the holes don't seem to heal or go away.. I have treated the tank for ick again but it hasn't worked. Does anyone know what causes pinholes in fins, they are on all fins except it's tail. I tried to google it but nothing comes up.
I don't think it's ick.
Please see my pictures, some of the the holes are really small, hope they are visible in pictures.
I would really appreciate any advice!
Thank you!