Snowflake clowns fighting?

[Jnickles85]

I have had my snowflake clown pair for almost two years. No issues at all besides the normal clown ocasional love tapping. Well today I walk in to the dinning room and I have one of my clowns floating near the surface skimmer. Kinda breathing hard and just looks exhausted. The other clown is swimming around fine and looks normal. Well I noticed that the sickly looking clown is missing pieces of his fins like a wild looking bird. So I just scooped him up and put him in the back partition of the main tank, just in case it's the other clown beating him up.

Anyone have any ideas why after two years they would just turn on each other?

Pic of other clown swimming on his own.

Pic of where the other clown was placed.

 

[Jnickles85]

Well, a few hours later and he's no longer in this world. Still not sure why the pair would wait this long before blowing up.