Is this fin rot or a result of aggression?

[Jiggs-Reef]

I am very concerned with my clown’s fin deterioration. I just introduced the aggression fish about two weeks ago and this has been progressively getting worse since then. I just took the video before posting. Thoughts?

Ph-8.4
Ammonia-0
Nitrites-0
Nitrates- 10ppm
Temp- 79 F

 

[MnFish1]

Given the timeline - it could be either. However the pictures point to aggression. And - aggression/fin damage can lead to infection. Unfortunately I can't see the video

 

[vetteguy53081]

I am very concerned with my clown’s fin deterioration. I just introduced the aggression fish about two weeks ago and this has been progressively getting worse since then. I just took the video before posting. Thoughts?

Ph-8.4
Ammonia-0
Nitrites-0
Nitrates- 10ppm
Temp- 79 F

The larger being female is clearly biting at fin in the video and should be isolated from smaller clown to avoid further damage. Place her in sump or acclimation box for at least 7-10 days and behavior may or may not change. You will then have decisions to make if behavior continues.