PMD

Anybody know the actual ppm where copper levels are considered unsafe for most freshwater shrimp in the hobby?

mistergreen

.4ppm is toxic to fish...

oblongshrimp

and aren't inverts much more sensitive? Basically any medication that has copper in it is probably not safe. Its in listed as in ingredient in the food though you are most likely safe.

Left C

I read somewhere that a few copper pennies dropped into a Red Cherry Shrimp nano tank will kill them.

PMD

Well, my tap water has 0.042 ppm of copper and my RCS are doing just fine. So, somewhere between 0.042 ppm and 0.4 ppm copper becomes deadly to inverts. I'm guessing that value is much closer to the lower number than the higher one.