Clown fins are shredded

[Tyrenlds]

One of my clown is starting to show slits in 3 of his fins... they're the only fishes in the tank and I have not witnessed any fighting between the two of them. Oddly, it is the bigger of the two. Is fighting the only cause of fin splitting?

 

[wicked_NaCl_h2o]

Fin splitting can be...
1. Fighting
2. The quality in the water is low
3. an invert is nipping at your fish..sally crabs, mantis shrimp or even a underfed coral banded shrimp.

There might be other reasons,these are the only ones I know of.

 

[Tyrenlds]

water parameters are tip-top. could limewater do this to fins? I've seen them swim through the return flow right as it was being added to the sump from the ATO, I quinced thinking that they got a direct shot of kalk water but they didn't seem to mind.