Zebra danio red stomach

[thefish13]

ZEBRA DANIO RED STOMACH
I have a 2 year old female zebra Danio which i recently moved into a smaller 5 gallon tank, there are red marks on her belly and I would like to know what it is and if it is contagious/curable

 

[absolutangel04]

That is usually a reaction to bad water quality. If you can test water, do so. But, even if you can't I would do some big water changes. Other options include internal bacterial infection or chemical poisoning. It is hard to say if it is contagious, because that us not an uncommon symptom.

 

[thefish13]

This is a fairly new tank setup and my other zebra danios in the tank are perfectly fine, I did a 3/4 water change yesterday