I'm aware that I am a bit late to the chat but I have A similar situation with my black moor, I have had him for about a month and a few days ago I noticed his clamped fins and then a white kind of film around his body. The way he swims has also changed, he is hiding much more and when I get him out of his hiding place to make sure he hasn't died or something, he swims very slowly for a bit and then would just go and hide again, and just about 20 minutes ago I got him out and now he is just staying in a corner and swimming into the glass and it's almost like he's waddling and wants to swim further but can't because the glass is there.
I'm not sure how to deal with this as he shares a tank with a common goldfish and I don't know how to go about treating him individually or the tank itself or just what to use or just what's wrong with him in general. I'm really scared as I love this fish with everything I have and any advice would really be appreciated.
Thanks so much, Alicia
(also forgot to mention that we also tested the ph and it said it was around 5 so I know it is too low but I'm still not sure how to fix that and the impact it has had on my little fishy)