They are lovely<3 Are all of them in the same tank?
They're in different tanks.
Pinkerton is in a 5 gal tank, it's why I'm wondering if he'd do better in a smaller one and stop the fin bitting. Mercury is in a 3 gal tank, and Monet is in a 2.5 gal one.
I've considered swapping tanks again, and putting Pinkerton into the 3 gal and Mercury in the 5 gal, but Mercury is doing excellent where he is and I'd hate for him to also develop a problem.