You Can Succeed with the Copperband Butterflyfish

Copperband Butterflyfish (Chelmon rostratus)

Copperband Butterflyfish (Chelmon rostratus)

Copperband butterflyfish (Chelmon rostratus) are among my favorite fish and have almost always been a staple in my tank since the saltwater hobby started in the 70s. It’s not just the beauty of the distinct black-bordered yellow stripes on a silver body, but the unusual shape of this species that appeals to me. The snout, which is almost as long as its body, ends with a weak mouth that is not designed for defense or much else except to eat soft-bodied prey (or perhaps to blow up balloons).

In the sea, much of that prey consists of worms that they can capture even in quite deep crevices in the rock. The only defense the fish has are the stiff dorsal spines that it will turn towards a predator, but it can take care of itself as those spines are sharp and it also has the ability to wedge itself tightly in a crevice in the reef.

A less-than-stellar survival record

Copperbands, like their close cousins, the longnose butterflies, are a little more delicate than the majority of fish we like to keep, and unfortunately their life expectancy in many home aquariums is dismal. But I know copperbands can live at least ten years as I, and many other people, have kept them that long.

Beware of jumping

They are inclined to jump if kept with aggressive fish, as they tend to back up toward the surface while they are pointing their dorsal spines at the aggressor. When I’ve lost specimens, it’s usually been to jumping, as my 100-gallon tank is only 14″ high and copperbands normally live in fairly deep water.

Shipping and handling damage

I believe the biggest problem with these fish is that they are often damaged in collection or shipping. A healthy copperband should have no marks on it, such as faint dark patches, raised scales, or lumps. I have found after autopsying dead fish that those dark patches are from internal bleeding, possibly by internal organs or muscle being pierced by a rib.

Any fish as thin as a copperband has its ribs almost right against the outside of its body with a thin layer of muscle in between. This “design flaw” is a huge detriment to these fish, as they are very prone to injury. Sometimes the injury goes unnoticed for a week or two, but then the dark patch gets darker and the fish eventually dies. There is no cure for this, and the fish never recovers. A fatter fish (or, to be PC, a “plus-size” fish), such as a clownfish, doesn’t usually have this problem.

Choosing a healthy specimen

A healthy copperband is always on the move and eyeing up possible snacks

A healthy copperband is always on the move and eyeing up possible snacks

The good news is, it’s fairly easy to pick a healthy copperband butterfly. If it is swimming around looking at you, the ceiling, or a picture of Paris Hilton on the wall, it may not be in good shape, as they are always hungry. Healthy ones will be constantly staring at something on a rock or the sand that they thought they saw move. If they don’t find it, they move on to the next possible snack.

I have swum with copperbands on the reefs, and they are always on the move. All fish with tiny mouths are always on the move because they cannot eat much at one meal, so they have to hunt constantly. That tiny mouth is not much good for killing anything larger than a fraction of an inch.

A fish on a mission

The copperband is not a particularly fast fish, but it is smart. The only reason it doesn’t do well on standardized tests is that it doesn’t have thumbs to hold the pencil, but trust me, it’s an intelligent fish. How do I know this? You just have to look at a tank full of fish and you’ll see. Most fish, like angels, tangs, and manta rays, just swim around aimlessly, but a copperband seems to have a mission. That’s how you can tell it is healthy. Copperbands also have personality, and each specimen has a different one.

Copperband diet

On the reefs, copperbands live on Aiptasia (indeed many hobbyists introduce this fish for the very purpose of eliminating these pesky anemones), tiny shrimp, fish fry, and worms. From my experience with captive specimens, some will eat Aiptasia, some eat only clams, and some eat only worms. But almost everything they eat is either crawling or sticking out of a rock. That is the purpose of that snout. They use it to pull tiny creatures out of their niches. So, as I mentioned, a healthy copperband should be constantly looking closely at either the substrate or holes in rocks.

The feeding challenge

The foods we feed to copperbands present another challenge. As I said, this fish is designed to eat soft-bodied, live foods, such as worms—and that is the preferred food for this fish. I feed them live blackworms and white worms every day. Of course they will also eat other things, but almost never will they eat flakes and pellets, which is something too many people try to give these fish.

Besides live worms, clams are on the menu

Besides live worms, clams are on the menu

Besides live worms, you can give them small pieces of clam. I buy chowder clams (actually, I make clam chowder for myself and keep some clams for my fish, as they don’t seem to like chowder and it is messy to feed). I freeze the live clams and then, with a sharp knife, shave off paper-thin slices. My copperbands will eat this until they can’t swallow any more, and because clams are a whole food (guts and all), the copperbands thrive.

The only other thing I give my copperbands is frozen mysis, but I like the clams better, as mysis is mostly indigestible shell and provides bulk but not much else.

Ask to see it fed

So, if you find a copperband that looks alert, seems to be searching for food, doesn’t have any discolorations or missing scales, and is not shaking or staring at pictures of Paris Hilton, then ask the store owner to feed it (something besides live brine shrimp, as even I will eat those). If it doesn’t eat, don’t buy it. I don’t care if the employee says they just got the specimen, it was just fed, it’s a little stressed from transport, it just woke up, or it has a headache (or athlete’s foot or any number of things); don’t buy it!

Hold the sawdust!

Copperbands do not always come from pristine reefs, as they are also found in silty tidal inlets far from the coral reef. They are constant pickers, and a slightly messier tank, in which they can hunt and hopefully find a snack, is better for them. I don’t want to make it sound like the copperband butterflyfish is the easiest fish in the world and can be kept in damp sawdust instead of sea water, but it’s definitely not as difficult as a Moorish idol…or a manta ray.


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About Paul Baldassano

Paul Baldassano has been in the hobby since the 50s and holds two aquarium-related patents. His current reef aquarium was set up in 1971. He is also an avid SCUBA diver and Vietnam veteran.


  1. Tohni Stelts says

    Set up my first saltwater tank about 3 weeks ago. 150 gal, water tested perfect (I have well water with softener) 1 of the first fish I purchased was a copperband butterfly. I have added some other fish since then. I was shocked to find out the CBB was supposed to be hard to feed, since I never had that problem. He has been fine and healthy this whole time. I did 20% water change over weekend and water still tested great. Woke up this am and CBB is laying on his side at bottom of tank. I have removed him and put him in 10 gal QT tank still the same. He appears to have a few red bruising mark’s or broken blood vessels on him. His white appears gray except on face and tail. Other he looks healthy, no bumps, white spots etc… could he have been injured by another fish or sea urchin? I did test water this am and its still good.

  2. Paul Baldassano says

    Sorry about your copperband problem but a 3 week old tank would not house anyone’s copperband as it takes at least three months for a tank to cycle enough to add most fish, but a copperband is more sensitive than most fish. You should start that tank with hardier fish such as clowns and gobies. Without seeing your copperband I can’t tell what is wrong with it but I am sure that whatever is affecting it, the newness of the tank will most likely kill it. No matter what your test kits read, your tank needs to have a sharp rise in ammonia, then a sharp rise in nitrate, two things a copperband will not live through. I am sorry about your fish but I can’t think of anything that will help it at this point. A copperband is a fish that is commonly collected with cyanide even though that is now illegal.
    Cyanide collected fish appear healthier, have brighter colors and may eat better, but unfortunately, they are doomed. I am not saying that is what is wrong with yours as I am pretty sure your tank is just to new.
    I doubt it was injured by another fish or urchin as they live in close association with urchins and a fish bite would be localized and usually only a fin is torn.
    The red blood vessels are a common symptom of ammonia poisoning and I am fairly sure that is what is killing your fish. The good news is that is what is supposed to be happening in your tank. Not the fish dying, but your tank is probably cycling normally.
    I would buy some smaller, cheaper fish “after” the tank is cycled using either some dead shrimp or store bought ammonia sold for aquarium purposes.

    • Tohni Stelts says

      Thank you very much for information. I wish fish dealer had told me this when I bought him, since he knew I had just bought the tank. I will heed your warning and stick with hardier fish. I’ve never heard of the cyanide problem and will read up on it. Thank you again.

  3. I just recently bought a Copperbend a butterfly fish. At the store I watched the owner feed it with frozen blood worms. It readily eight, I give it two days in my aquarium before he attempted feeding. I put in the Thawed frozen blood worms, 88 a few but left the rest alone. Is it eating enough? I also put some thawed frozen adult brine shrimp in, But it ignored that. Is this acceptable peek? And can I assume that it is eating healthy?

    • I am sorry for my spelling and grammar. I am not very good at language arts. I hope you can understand what my original question is.

  4. Joshua, those two foods you are feeding is not a good diet for any fish, even if it eats it. Bloodworms are not really worms, but insect larvae not suitable for salt water fish. Brine shrimp are also not a good food for anything. If you can’t get blackworms, use clams. The same type that humans eat like I showed in that article.

  5. I bought a CCB about 10 days ago. She’s eating well and foraging through the rocks.
    It’s hard to feed her, because my Scopas Tang (the pig), Dwarf Coral Beauty (a piglet), and the Yellow Wrasse. I chop up fresh clam, stuff it into holes in a reef rock, and put it in the same place every time. She will saunter by drop down and swim away. A few minutes later (after trying to keep the pigs away), she will come back and eat some, then swim away. Then the pigs move in to finish the rock o’ clam off. And what they can’t reach the crabs get it.


  6. I have purchased a Copperband and pick it up later this week. Thanks for the article it has helped a lot.

    • Mark, I just saw this. Yes, I know a year late. To feed a copperband when faster fish are around you can put some food, preferably clams in a see through plastic container that has some 3/8″ holes at the bottom, hang it in the tank off the bottom. The copperband will stick his snout in there to get the food but the other fish will not be able to reach it. You can also take a plastic tube about an inch in diameter and 3″ long. Glue some small “barriers” in there maybe 1/4″ high so the food will stay in the center inch of the tube. Lay the tube on the bottom, The barriers can be any scrap pieces of plastic that rise up a little from the bottom of the tube just enough to keep the food in there. The copperband should be the only fish to reach it. I have a picture of that in my book where I am using it to feed a mandarin

      • Hi, Paul
        I am trying to get rid of aiptasia’s I have a lot in my sand bed how do I get rid of them
        I have heard people have used lemon juice. Some have used vinegar . What do you
        Thanks Rob.

  7. This is a great article on a fantastic fish. I’ve had mine for about 3 years with very few problems.. You have to train them to eat out of the water colloum as it’s Not natural to them, but mine was a very fast learner. Now he almost eats out of my hand. He’s gotten clams and worms a few times but I mostly feel music enriched with plankton and brine enriched with siprilnella. I also keep my overflow and sump full of apasiata do he must get some of those when they try to spread. I haven’t seen a trace of one in the main tank since he showed up. Beautiful, intelligent and idle of personality, he’s easily my favourite fish.

  8. Hi Paul,

    I am investigating adding a CBB to my 180 reef. Yep I feed live clams and black worms to my tank after finding your articles a few years ago. My question is that in my 180 I also am adding a male / female mandarin (tank raised.) Does the Copperband also eat copapods? As in will my CBB compete with my mandarins for pods on the rock? I am nervous that my tank will not sustain all three fish. I was going to keep a refugium for pods and also hatch brine shrimp weekly. Will the CBB eat the baby brine shrimp? I remember reading a post from you where you shared that you used to collect food for the CBB at the docks? That they actually eat sponges? Can you provide more detail and a photo?

    More feeding questions bc I do think proper feeding equals healthy fish! You never mention feeding fish oysters only clams? Why is this? I am trying to keep their diet varied for health so I give clams / steamer clams / oysters / mussels / shrimp / scallops. Why no mention of oysters? Also since I have been feeding more live food it has been hard to keep my nitrates low… They are going up.. and currently I am at 20/40 nitrates? What do you think is acceptable nitrate level and how do you manage this? My tank looks good and corals are growing…


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