First of all, a copperband is unsuitable for a 45 gallon breeder tank. Too shallow, too small.
I must start a web site up for this. I have some pics of copperbands that I will post as soon as time permits. Mine have tended corals of all kinds and if an observer wasn't watching carefully, they would think the copperbands were after the corals. I have a picture in my gallery that is there because the copperbands have kept that pipe organ from being parasitized by various species of polycheates. They can remove the tiniest of near microscopic aiptasias from the side of a zooanthid swifti polyp without even making the polyp close up. That is surgical precision. Another picture in my gallery shows a hot pink pocillopora eydouxi that is alive today because the copperbands took the dead polyps and tissue off from it and kept it from getting some nasty infection. I got it dead - now look at it. There is no way I could have done that. Some observers would report that the butterfly ate the coral. I would say the butterfly is the reason its so beautiful today. I put a maxima clam in with the copperbands. Out of the corner of my eye, I thought I saw and attack, but, then I saw it -- a little aiptasia that I inherited with the clam. After the pseudo-attack, the clam was clean. Today the clam - its awesome. There are some tricks to doing this though. Had I listened to the "experts" I would not have polyps of all sorts and kinds including yellow polyps, woods polyps and every coral type under the sun in with them. Copperbands are very specialized feeders. I have a bicolored blenny that does damage to sps corals. The copperbands never have. They also do not bother gorgonians at all.
What they DO eat: Snail antenae, except for nassarius snail antenae. Feathers of calcite encrusted feather dusters, all of the feather, tube and worm of little cluster dusters, polycheats (including bristle worms), aiptasia, astrea snails, small pods and shrimp (although not able to eat large gammarus shrimp unless they can hang on to them long enough to crack the shell), live mosquito larva, live cracked black mussels and white cultured clams when placed on the bottom and split open. Actually, they love bivalves and love the treat of one split open on the bottom of the tank. All the fish get in on that feast.
After conversion to aquarium life, a feat that many people can not accomplish, they eat frozen foods including shreaded clams, mysis, krill that is not in gel, brine, etc. They hunt and feed from first light to the last little bit of the moonlights. Needless to say, they need to be fed often and should have full bellies. Often I have seen these fish come in with so many parasites that its very difficult to clean them up and get them converted to tank life. Once converted, they will be your favorite fish as they readily take frozen mysis and krill from your hand. They will even try to eat your fingers on occassion. No teeth, so they don't draw blood. They may poke their snouts down into live sand to capture small worms. All this seems to be beneficial as there is some turn over in the tank and new worms are always present. I still have small worms appearing, they are just kept from over running my tank, and in this is special concern for my pipe organ coral. All I can say is thank you God for creating such a specialized feeder that keeps my pipe organ worm free. I have some awesome zoos and different species of star polyps. I've seen the copperbands remove small aiptasia from within the polyp colonies. They never touch the colonies at all, but, an inexperienced eye would immediately rip the zoos or stars out of their tank or capture the copperband. Me -- I let it play out for a while. I am glad that I did as I saw the aiptasia in those polyp colonies and was wondering if the copperbands would go in for the save. Sure enough, they did. I have 4 large hawaian feather dusters in the tank and all have their feathers today. They're just faster on recoil than they once were and the copperbands aren't all that interested in them anymore. So, all that said, I'll take my copperbands over a few worms and snails any day.
Its so difficult to get healthy ones and get the parasites off of them and convert them to captive food. I hear of experts in maast loosing them too. So, this is not something you should try unless you are very experienced in reef keeping and taming the wild fish. There is a marked decrease in the populations of copperbands in some areas, so, due to the high mortality and complexity of problems with these, they should only be attempted by experienced folks with larger mature tanks. They need some space and a 45 gallon breeder tank is really too shallow, too small for long term keeping. Only one to a tank, due to the age of the fish we get as at that age they are not schoolers and need somewhere around 5 feet to 5 yards of space between them. There are also exceptions to this, but, only for the experienced with large tanks like a public aquarium would have.
Questions, just ask.