Pond Goldfish In Trouble

[30tooo]

My friend accoss the road asked me to look at one of the fish in one of his two ponds . The attached pictures tell you of my horror .
The green stuff looks almost like a moss . There maybe two or three more fish in the same sort of trouble .
I know this for tropicals , but I have had great advise from here before and it is the only place I could think of as well .

This is the other side .

 

[WILDER]

That fish has bad bacterial infection, wouldn't worry about the green it could be algae sticking to the dead tissue.
Size of pond.
How many fish and which type.
I would get the pond water tested at the lfs and tell them to write the readings down for you.
Bacterial med for the pond fast.

http/www.fbas.co.uk/Ulcers.html