Tracey wrote:

Hi, I'm new here and could do with some advice.

To cut a long story short a couple of goldfish in my pond developed a
fungal infection (I think the first one had an injury to start with
that I didn't spot until it was too late). Treated the pond with a
couple of courses of malachite green, which didn't help with the
fungus.

I resorted to buying a hospital tank and have treated both of the
goldies with Nifurpinol on the advice of the aquatic store.
Unfortunately, the worst affected of the two didn't make it. The other
is very lively, feeding well and the fungus looked like it was going
away. However, it has now developed a reddish black ring around the
infected area which looks quite nasty. Is this normal healing or is it
a sign of something even more nasty?

Also, if this is getting better, when would it be safe to return the
fish to the pond (it's really not happy in "prison").

Any advice will be greatly appreciated.