Keep in mind that copper will also kill shrimp and crayfish. There is some evidence that some types of copper will penetrate decorations in the tank, and then leach out in low levels for a long time. If you have ever considered adding invertebrates, do not use copper. If you ever plan on converting the tank to marine, do not use copper.
Copper is a toxin. Not fish friendly.
Copper is a toxin. Not fish friendly.