Marine Betta - Tail Fin Issue

[Michael Hull]

Hi all,


Tank is otherwise VERY healthy, but noticed that our Marine Betta (who is the queen of the tank) has some fin damage that looks to be fin rot (I can't find much intel on that for saltwater fish). Can anyone advise? Is there a tank-wide antiobiotic I could use?

Recently chemicleaned for a Cyano issue, but did water change, parameters are solid, corals are thriving and all fish are thriving. No algae issues. No mean fish that I can think of.

Pic attached.

Thoughts??

 

[Dom]

All that blue makes it difficult to see...

Have you recently added another fish that may be bullying?

Is the problem localized or is it just the tail fin?

If there is a new fish in the tank, I would think tail fin nipping during aggression.