ALL sources seem to agree that your water quality must be PERFECT to keep copper bands. It appears that they like a bigger tank. I don't know what the minimum size is but it's worth looking into.
Reports are that CCBs starve really fast. If they aren't getting enough or proper food type, they can die very suddenly. Most posts say their CCB lived for weeks or even months but I didn't find any that said they've owned one for years. That doesn't mean that it doesn't happen. It does suggest that they are very sensitive fish.
Here's some opinions from other sources since I was curious. I googled copper band butterfly death and found these:
from saltwaterfish.com ( underline mine )
The Copperband Butterfly is one of the few Butterflies that is commonly distributed for the home aquarium. These exquisite fish are silvery-white in color with orange vertical bands, as well as a "false eye" at the rear of their dorsal. The Copperband has an elongated mouth which it uses to pick at coral heads, including nuisance Aiptasia. These fish will accept many fish foods, but require excellent water quality. The Copperband is very docile and gets along well with other community fish. These fish will also eat nuisance glass anemones (Aiptasia). It is best to only keep one per tank.The family of Butterflyfish get their name from their behavior of fluttering around the reef. These fish typically have rather round and thin bodies. They are very colorful and some have extended snouts which they use to reach worms entrenched in the reef.Photo by Saltwaterfish.com member, mx#28
From thereeftank.com
Copperbands ARE a cyanide-targeted species. Not all copperbands are caught that way, there are net-caught available. Depends who your LFS buys them from.
8 days in the LFS, plus a week in transit from the collector to exporter to importer to LFS is realistic for a juiced fish to live. Some live hours, some days, some a few weeks. Some can live for years if the concentration wasn't that great, and the fish tolerated it well.
It's hard to track where the fish came from, and if it might have been squirted -- There are a lot of lies in this industry.
If your LFS is picky - they can find themselves net-caught specimens. Not knowing the store and not knowing who they are buying from, I'm not going to leap to a conclusion regarding this particular specimen (and I don't want to know what store...not trying to cause conflict), it's entirely possible that this one just failed to thrive - that happens occasionally even with net caught (but a LOT less frequently).
Make sure the fish is eating in the LFS and feed it whatever the store was to get it to keep feeding, and know your store, and trust them. If you can't be sure about the capture methods, I suggest you avoid the species that are usually targeted. That's the only real way to assure clean fish.
to much fun, esp giving one a hard time by siding with the other
