One of my crowntails has fin rot. Fish that have fin rot have missing fins (they're ripped or some of the fin is gone). It's a bacteria that eats at the fins. This is the first time that I've had to treat my fish for this and I asked lots of questions on this forum about it and a lot of people helped me out. If you could take a picture of your fish, that would help us figure out what it is.
FredFish has fin rot as well. I believe bacterial bloom caused the cloudiness several days ago. I did a 10% water change (with disolved salt) four days ago the bacterial bloom was gone when I came home from buying the 5g. Neverthless, I started FredFish on Mara-2 yesterday.
He is not as perky as he was, buy I think it is due to the 2 partial water changes. He did blow his first baby bubble nest while I was away buying the 5g. Nice surprise when I got home.
Aquarium salt works SOOOOOOO good! I didn't even know Bernard was missing finnage and two days ago I started adding it to his water during water changes. I can see the fins healing! The tips are translucent and they are getting much longer. Definitely a must have. Works wonders on fin rot and will help gill function even if he doesn't have it. Better safe than sorry.