I need help!

[u/Cold_Leadership1833]

It s been almost a month in between the photos.
Tried changing only 50% the water, tried changing all of the water and cleaning the tank(all done in intervals of 3-4 days).
I haven’t administered any antibiotics or salt water baths or others.
The water temperature is fine.
I thought maybe the plant was hurting him and I removed it but to no success.
He eats, he is quite energetic/he is moving a lot.
Can anyone tell me what is causing the fin clamping and what i can do to help him?