What is the red fungus on the fish in our pond?

A lot of the fish that we have caught are have a nasty looking redish fungus on their scales. I know you can still eat them if you cut it off, but I can't make myself. Can you tell me what it is, what causes it, and how to get rid of it?What is the red fungus on the fish in our pond?
More likely than not, it's simply a regular fungal infection. As the hyphae are exposed to water flow, particulate, including suspended red algae, gets trapped in them, giving the fungus a red appearance. I would really not recommend eating the fish-- much of the tissue is likely already digested by fungal enzymes, and some of these fungi are toxic if ingested. If it's your private pond, I'd recommend treating it with potassium permanganate, copper sulfate, or formalin. These are all highly damaging to microbial life (including fungus), however, so they shouldn't be used if the pond is anything more than a holding container for fish (i.e. part of the ecosystem).