Help for my zebra danio

Hi all,


One of my zebra danio fish has an infection like thing near gills. Its been like that for nearly 15 days.
I do regular water change and cleanup regularly . Attached photos
Other fishes in tank : Koi Angels, Neon Tetras, and Zebra Danios

Is this an infection which can spread to other fishes or an injury ?

Hi and welcome to the forum

It looks like a gill tumour and there is nothing you can do about it. They normally take more than a couple of weeks to get that big so yours appears to have a very aggressive form.

They aren't normally contagious and you simply euthanise the fish when it has trouble breathing, swimming or eating.