Help! Clownfish fins damaged

[Reefing Mama]

I have had 2 clowns that have been a bonded pair for almost a year. This one that was exhibiting signs of dominance until recently, and I assumed was the female, has now been obsessing over the powerheads the last few weeks and yesterday she was fine minus a LITTLE fin fraying. Now her fins are almost gone! In a day. I have since moved her to qt and I'm monitoring her but idk if it was the other clown or fin rot or what. There are no other fish in the tank and have not added corals or inverts for the last 2 months. @Veteranreefer

 

[Reefing Mama]

Here is another shot

 

[Veteran Reefer]

Its been very weird to say the least and has carried on for a few months.