Betta fins damaged: why it happens when water is fine

Betta fins can get damaged for a few reasons. Fin rot is often linked to poor water quality — but if your ammonia and nitrite are zero and nitrate is reasonable, the cause is usually physical: tank mates nipping, sharp decor, filter flow, or the betta biting its own fins.

Our full guide to betta fin damage walks through each cause and what to do when water parameters are OK. See also fin rot, betta tank mates, and betta care.