I used to manage the thousand gallon public aquarium at my community college campus (OCC) and we deal mainly with saltwater.
Copper is forbidden for any piping in our building because we've had mass die-offs when we unknowingly put copper piping in our automatic top-off system.
So much hated is this metal that when the building was first built and designed, one marine biologist Professor Dennis Kelly decided to stand by and watch them install all the copper piping for the building before telling them that it was in their contract to avoid metals like copper. Needless to say they had to redo all the piping and we had to hear about it during class.
Then came a huge lecture about what to use and what not to do when it comes to system water. You won't begin to believe the amount of [censored][censored][censored][censored] you're not allowed to use in the water.