Hi wise people,
I have recently re-started up my tank (130l) and my first new batch of fish are ones someone I knew was getting rid of as she found she couldn't keep a tank (a group of zebra danios and a single molly).
However, I noticed when I got them that one of the danios had a mark on its side. When I asked her about it she thought one of the others had had a nibble of it.
Two weeks on and the fish doesn't look great. The fish itself is looking v fat (very constipated or pregnant 😱) and the damage on its side looks nasty. When doing a water change today I netted it to have a closer look and I'm not happy.
How would I know whether it will heal or whether I should euthanise the fish? I was also hoping to buy some tank mates tomorrow and am now worrying whether it was a nick or could it be ill in some way that may spread???
Don't know what to do for the best 😞
Thanks in advance.