In Va. copper coils+fire= jailtime.
Just tell the judge you were only making antifreeze for your pond
Now I know my brain is half-fast! I didn't realize you were referring to how my neighbors use of copper tubing and wood heat!

That may not warm up the water, but it might keep it from freezing.
Unfortunately, what comes out of those copper pipes is what I use to instantly euthanize fish so I can send them off for a fish necroscopy (fish autopsy) -- even if they aren't sick!
Yeesh. This whole thread all leads to what we do to fish when we treat them like college students.
We make them drink too much so they will throw up. After we figure out what they had for dinner, we give them way too much booze, and they die from alcohol poisoning. Then we send them off to the coroner, who figures out what made them the way they were!
