I have lost 4 out of my 5 goldfish. The last one I noticed was very lethargic towards the end and hanging at the surface of the pond barely moving. I put him in a separate tub and noticed he has what looked like little white strings hanging around his mouth and some on his body. From my google searches I think it may be anchor worm. Has anybody had run ins with this or other parasites in their pond? I have one fish left in the pond (8ft diameter stock tank) and am considering taking him out and treating him in a separate container if needed. I read that Potassium Permanganate can be used to treat them. However I am open to whatever will work. I assume the whole pond should be treated.