gill curl

Hi Everyone- Noticed the gills on my two red tail cats are starting to slightly curl outward. It comes and goes though, doesn't flare out all the time. They are in my 500 gallon. 0 ammonia, 0 nitrite, nitrates I battle, but usually stay around 80-100 ppm. Pictures below.

Hi Guys, As we are all aware, the current pandemic is effecting us all. As Dubai is 90% foreigners. A few people had to go home in a hurry, or seriously downsize their lives. Unfortunately this leaves a lot of animals in a poor situation, including fish. Quite a number have been dropped off at...

One side of my gar's gill looks like this. Is that gill curl or damaged gill? It might've damaged itself since the tank at my LFS was pretty small and was pretty crammed.

I have been getting conflicting advice/info on what to do about gill curl, and how it's caused. Some say its genetic and some say bad water quality, but i am a wc fanatic...i dont see how that would be possible. What i need is a cure...some say to do the surgery but i havent seen any proof that...