any relationship between large bodies of water and our ponds is imaginary. large
bodies of water have water flowing in and water flowing out and flushing the system.
The number of gallons per fish is a great deal higher so the concentration of the
parasites is a great deal lower. Despite that, fish are dying from disease all the
time in large bodies of water. A large part of natural selection is having the
immune system that can withstand parasites, bacteria and viruses.
Try Noga, he gives the source of infections that hit all kinds of fish. Ingrid

Lori wrote:
Do you have documentation to back up that statement? Just curious,
since ducks, geese and other birds poop in all types of water bodies
that contain aquatic creatures, with no evidence of harm to the water
creatures.