I could not help but do some reading on the darned things because they are so unsightly and reduce people's desire to eat the fish. I found a thesis paper here...

https://digitalcommons.liberty.edu/cgi/viewcontent.cgi?referer=http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=2ahUKEwi6gq3rhNncAhVBS6wKHUJrCuIQFjAHegQIAhAC&url=http%3A%2F%2Fdigitalcommons.liberty.edu%2Fcgi%2Fviewcontent.cgi%3Farticle%3D1192%26context%3Dhonors&usg=AOvVaw3yj9kYKK3yCuylYc1wMJfn&httpsredir=1&article=1192&context=honors

That states..."This disease does not pose a threat to humans and thus does not require extensive prevention."..."The best way to prevent black spot disease in fish is to disrupt this parasite’s life cycle by decreasing the number of intermediate host snails."

And this..."An organism infested with parasites is considered to be sickly; however, a rich parasitic community can indicate a thriving stream environment."

And..."About 95% of the diet of the Redear Sunfish is snails (Goodman, Marschall, & Stein, 1984). This characteristic makes this fish particularly fatal to the Black Spot life cycle."

WELL, the article also talks about snail poisons (molluscicides), but later states that the snail predators, like Res or Malayan snail eating turtles, are the most cost effective means to reduce the parasite.

SO, The bad news is there's no quick and easy fix.

The good news is...the parasite is generally harmless and is an indicator of a healthy environment. For the most part, according to the article, this "healthy environment" means little to no pollutants.

Journeyman, no mention of salinity or water quality changes. The cures revolved around knocking out one of the hosts (fish, birds, or snails) and snail poisons will often kill the fish too.

Good thing my fish supplier gave me a lot of extra RES because he was afraid the long trip home might be hard on them. I ask for 50 and he gave me almost 100 and they traveled and transplanted well. They just need to get to eating the snails which I see very few of anyhow.

Fish on!,
Noel