This is a species that can benefit from quarantine for reasons that have nothing to do with pathogens or parasites. A copperband, even if it chooses to eat, will not compete well with other fish until it has had some time to acclimate to captivity.
If your copperband is reluctant to eat, try some live black worms. My copperband cannot resist these and they are much more nutritious than brine shrimp. Worms are a significant part of a copperbands diet, so it is not a great leap for them to accept a freshwater variety. My other fish go crazy for them now, too.
My copperband went nuts when I moved it out of quarantine and ended up with a red nose, ala W.C. Fields. The red was gone within hours, though, and it never seemed to affect it.