Hello all, about two weeks ago I received several beautiful female bettas that were shipped by breeders. The shipping process was rough and took way longer than it was supposed to, but all the fish arrived alive, although a bit dull with some torn fins. Their colors and fins are starting to look better and they are eating and swimming well.
However, one hasn't improved. She was beautiful and healthy in the pictures from the breeder, but after shipping, her scales appeared to be flaking off. It still hasn't stopped, in fact it seems it's gotten worse. She's active, but not eating as well as the others.
Water temperature is 80 F / 26.6 C, and the pH is roughly 7. I do 10% water changes daily, about 10 hours of light, low-light plants with no fert dosing, and a HOB filter set fairly low to avoid too much current.
I've read this can be due to fungus, but others say bacteria. I've been using a little bit of API Stress Coat during water changes. She's housed with the other female bettas, are they at risk of contracting the same infection? Should I quarantine her? If so, what treatments should I use (or can I use any treatments while she's in the community tank?)