It loks like fungus growth. Since your fish are in a quarantine tank. Maybe try adding some anti-fungus treatment. From the picture, the tetras look like they have fin rot too. With so many outbreaks at once, it is quite possible water quality is causing this. Is your tank cycled and established? In my experience all tetras need very good water quality to be healthy. Sometimes the fish are already unhealthy when bought and the journey from LFS to home tank caused stress which caused the outbreaks![]()









Reply With Quote
Mouth fungus is caused by bacteria too and so is fin rot. Looks like the nipping opened up wounds for bacteria infection.


Bookmarks