I saw a couple myself in the river...pretty weird
common in summer time. especially fish in or rescently form the river. warm water breeds bacteria. They get viruses/sores just like any animal can.some of the fish we caught sat night, had round 1" round red sores on there sides.
Exactly what I was thinking. A lot of people dropshotting fish in 20-30ft right now too.I would say your seeing the result of fish caught and released, going down a bank and catching ten rats and throwing them all back would have this affect if they were not fizzed before release, if deep enough. I know we were fishing twenty feet and deeper and releasing all our smaller fish.