goldfish with unknown problem

[Geezer]

I clean two indoor ponds in an office block.Water tests fine in both and the water is very clear.A small comet in one of the ponds does'nt look too good.Looks like it has swallowed two five cent pieces and has what looks like tiny cysts with white puss excreting from them.Have been dosing with pond melafix which seems to have helped a little.Does this sound familiar to anyone?All the other fish seem fine but am worried now that it could spread to them.Dont want an epidemic on my hands.Cant bring myself to sacrifice the little fellow!He is still eating but seems to sit in the corner away from the others.??????????????

[Alan]

Take the fish out of the pond and put it into a separate receptacle.

You must be using gallons of malachite green to treat the fish properly.

of course, depends how big the pond is as to how many gallons you should be using.

Also, if it is contagious, the others will have less chance of contracting the problem.

Alan