Beaked Coralfish, Beaked Butterflyfish, Longnose ButterflyfishFamily: ChaetodontidaeChelmon rostratusPhoto © Animal-World: Courtesy David Brough
Getting a Copperband Butterflyfish is like choosing from a box of fine chocolates, each is a unique individual!
The Copperband Butterflyfish Chelmon rostratus (previously Chaetodon rostratus) is a very notable species especially with its elongated snout. it is moderately small, reaching not quite 8 inches (20 cm) in total total length. Yet it is very attractively colored with an elegant form and graceful swimming movements.
This is one of three species in the Chelmon genera, all of which are noted for having longer beaks. These butterflyfish have a long snout especially adapted for feeding on benthic invertebrates dwelling in small crevices in reefs and the substrate. This feature has led to a number of common names this fish is known by including Beaked Coralfish, Beaked Butterflyfish, Longnose Butterflyfish, Beak Coralfish, Banded Longsnout Butterflyfish, Copper-banded Butterflyfish, and Long-beaked Coralfish. Other butterflyfish with an extended snout are in the Forcipiger genus which include the popular Yellow Longnose Butterflyfish Forcipiger flavissimus.
This pretty butterflyfish is commonly available and reasonably priced, however it is delicate. The ease of keeping this species varies from one fish to another. Getting a Copperband Butterflyfish is like choosing from a box of fine chocolates. Each is a unique individual and though there are clues, you won't know exactly what you've gotten until you have one. Some will be easily adapted and maintained while others refuse foods and perish.
Success in keeping this delicate species varies between the individuals. They can be finicky eaters and require very high water quality so are not recommended for beginners. They are best kept by intermediate or advance aquarists. The best success in keeping this species is in choosing a healthy well fleshed out individual, avoiding any that look emaciated. It is reported that those from Australia may do better than those from other areas. This possibly reflects the methods of collection and transport. The Australian specimens usually cost a bit more than those from other areas.
This fish does need a more spacious aquarium than other butterflyfish of similar size. It is quite active and will swim freely in the open water, but it also spends time hiding in cracks and crevices where it will lie motionless. It needs larger furnishings like table corals where it can hide or keep motionless as well as open areas to swim. It can do well with a variety of other less aggressive species in a fish only community tank. But it is aggressive towards others of its own kind and possibly towards other Chelmon species. It will usually be fine with other butterflyfish species but an occasional adult may become aggressive.
Keeping this butterflyfish in a reef environment is a judgment call. Success will depend on what other types of reef inhabitants you are keeping as well as your individual butterflyfish's tendencies. They are not generally coral feeders but may nip at the polyps of large polyp stony corals, and they enjoy polychaete worms.
For more Information on keeping saltwater fish see:
Marine Aquarium Basics: Guide to a Healthy Saltwater Aquarium
Australian Copperband Butterflyfish (Chelmon rostratus)
- Size of fish - inches: 7.8 inches (19.81 cm)
- Aquarium Hardiness: Moderately Difficult
- Range ph: 8.1-8.4
- Diet Type: Omnivore
- Minimum Tank Size: 70 gal (265 L)
- Temperature: 73.0 to 81.0° F (22.8 to 27.2° C)
- Temperament: Peaceful
The Copperband Butterflyfish Chelmon rostratus was described by Linnaeus in 1758. It was first collected in the Indian Ocean and was described as Chaetodon rostratus. They are found in the Northeastern Indian Ocean and the West Pacific; Andaman Sea to the Ryukyu Islands, Southeast Asia to the Great Barrier Reef, Papua New Guinea and the Solomon Islands. One record of an adult specimen from southern Honshu, Japan was made, but it seems to be a waif from the Ryukyu Islands or perhaps was an aquarium release.
This species is on the IUCN Red List as Least Concern (LC). They are found in a variety of habitats and not restricted to coral reefs. They are the most frequently caught for the aquarium trade, but there are currently not any major threats to this species. Other common names they are known by include Beaked Coralfish, Beaked Butterflyfish, Beak Coralfish, Banded Longsnout Butterflyfish, Copper-banded Butterflyfish, Longnose Butterflyfish, and Long-beaked Coralfish.
In their natural habitat they are observed singly or as a pair of adults in coastal and inner reefs. In estuaries juveniles can be observed alone or in a small group. This species dwells at the depths between 3 - 82 feet (1 - 25 meters). With their elongated snout, they are adept at feeding on benthic invertebrates from small crevices, most likely feeding heavily on tubeworms and small crustaceans.
- Scientific Name: Chelmon rostratus
- Social Grouping: Varies - Seen singly or in pairs as adults. Juveniles are solitary or seen in small groups.
- IUCN Red List: LC - Least Concern
The Copperband Butterflyfish has a disc-like shaped body that is laterally compressed and it has a long protruding snout tipped with a small mouth. The dorsal fin is continuous and it has a rounded tail fin. This species can reach almost 8 inches (20 cm) in the wild, but most specimens available are are less than 5 1/2 inches (14 cm) in length. The average lifespan in the aquarium for this species is about 4 years, though in the wild they live approximately 10 years.
The body of the adult C. rostratus is silvery white overall with four vertical orange bands on the side, each with a blackish edge. The first passes through the eye and the last is obscured on the top and bottom,
The dorsal and anal fins are white, edged in yellow with a bluish submarginal line. The body bands extend across the fins and there is a black ocellus in the upper portion of the last band that has a bluish white circle basally. The caudal fin is whitish fading to translucent, and there is a vertical black line on the peduncle with an orangish band just behind the black. The pelvic fins are orange with a vertical white bar centrally.
Juveniles are very similar but the ocellus on the dorsal fin is larger, and the orange bars are more conspicuous with each edged by black.
The Copperband Butterfly is very similar in appearance to its close relative the Margined Butterflyfish Chelmon marginalis. As juveniles these two species are virtually identical, however as adults they can be differentiated by their color pattern. As the Margined Butterflyfish matures, the narrow mid body bar disappears and the ocellus becomes obscure. It is thought that these two species may hybridize in areas where they co-occur.
- Size of fish - inches: 7.8 inches (19.81 cm) - Most specimens available are are less than 5 1/2 inches (14 cm).
- Lifespan: 4 years - In captivity they can have a lifespan of 4 years, possibly more with good care. In the wild they live for about 10 years.
Success in keeping the Copperband Butterflyfish varies between the individuals and so are suggested as best kept by intermediate or advance aquarists. Some will quickly accept fresh and frozen foods and be easy to maintain. Others will refuse to eat initially, but may be enticed to eat live foods if offered in a way that simulates their natural feeding environment. Yet still others will refuse foods entirely and ultimately perish. Juveniles tend to accept various foods and so can often be more adaptable to aquarium life than adults.
- Aquarium Hardiness: Moderately Difficult - The level of difficulty varies between individuals. Some readily adapt to the aquarium, some are finicky and slow to adapt, and others simply perish.
- Aquarist Experience Level: Intermediate
The Copperband Butterflyfish are primarily carnivores. They are known to feed on benthic invertebrates in the wild, and they are believed to feed heavily on tubeworms and small crustaceans. In captivity some will quickly accept fresh and frozen foods and be easy to maintain. Others will refuse to eat initially, but may be enticed to eat live foods offered in a way that simulates their natural feeding environment. Bloodworms pushed into rocks and corals, or live clams and black mussels with their shells cracked open have been reported as successful for these. Yet still others will refuse foods entirely and ultimately perish.
Offer a variety of meaty foods, dried flakes, prepared frozen foods, and tablets. Vegetables like lettuce or Japanese Nori (Asakusa-nori) may also be favored. Offer various foods quite frequently at first. Feed it at least twice a day. If it is a tiny juvenile, food should be provided frequently in small quantities three or four times everyday. Once it is successfully acclimated it can become a fairly hardy fish, but for how long is unknown.
- Diet Type: Omnivore - They are primarily carnivores, but may feed on some vegetables.
- Flake Food: Yes
- Tablet Pellet: Yes
- Live foods (fishes, shrimps, worms): Some of Diet
- Vegetable Food: Some of Diet
- Meaty Food: Most of Diet
- Feeding Frequency: Several feedings per day - Offer various foods quite frequently at first. Once acclimated adults need at least 2 feedings a day and juveniles need 3 to 4.
It swims freely, spending a good deal of its time in the open water but also needs larger decorations that provide many places for retreat where it may hide or keep motionless. Frequent water changes are not necessary, rather normal water changes at 10% biweekly or 20% monthly are fine. Sudden massive water changes can cause trouble.
- Water Changes: Bi-weekly - Change 10% biweekly or 20% monthly and avoid sudden massive water changes.
These fish need a lot of space to swim as they can reach about 8 inches in length. The tank needs larger furnishings like table corals, or lots of rock/ corals with many cracks and crevices where it can hide or keep motionless. This is especially necessary for juveniles but is also important for adults. For this type of decor it requires an even more spacious aquarium than other butterflyfish of similar size. A 70 gallon (265 liters) tank is the minimum size for a single fish, and a bigger tank will be needed if you want to keep more than one.
Keeping the Copperband Butterflyfish in a reef environment is a judgment call. Success will depend on the individual fish as well as what types of reef inhabitants you are keeping. A pro to keeping it in a reef tank is that some individuals will munch on those pesky Aiptasia species like the Glass Anemone Aiptasia pulchella, though it can be a hit or miss, depending on the individual. A con to keeping it in a reef is that polychaete worms are a favorite (and natural) food, and it will most likely have a heyday with them. Many aquarists report that when kept well fed, their Copperband Butterflyfish doesn't bother any of their reef species.
In his excellent book, Angelfishes & Butterflyfishes: Reef Fishes Series, author Scott W. Michael says that many of the soft corals with the exception of some of the zeniids, clavularids, and zoanthids can be fine. Also many small polyped stony corals will do fine, though it may nip on the large polyped stony corals.
- Minimum Tank Size: 70 gal (265 L) - A larger tank will be needed if you want to keep more than one.
- Suitable for Nano Tank: No
- Live Rock Requirement: Typical Plus Hiding Places
- Substrate Type: Mix - Sand + Coral
- Lighting Needs: Moderate - normal lighting - It is best kept under the normal lighting conditions, but can also be kept under very bright light as long as some dimly lit spaces are provided.
- Temperature: 73.0 to 81.0° F (22.8 to 27.2° C) - This species lives in tropical areas. Temperatures of 73 - 81° F (23 - 27° C) will serve them well, avoid temperatures higher than 86° F (30° C) or below 69° F (21° C).
- Specific gravity: 1.020-1.025 SG
- Range ph: 8.1-8.4
- Brackish: No
- Water Movement: Weak - Water movement is not a significant factor. It can tolerate a rather strong flow but slow-moving water will be more favorable.
- Water Region: All - It is quite active and will swim freely in the open water, but it also spends time hiding in cracks and crevices where it will lie motionless.
This is a not an overly aggressive fish, but it is territorial and will be aggressive towards other members of its own kind, and sometimes other butterflyfish in its same genus, Chelmon. Not so aggressive angelfish like members of Centropyge, Apolemichthys, Genicanthus, Chaetodontoplus and Pygoplites can be good tank mates. Good candidates as tank mates include smaller non-aggressive fishes like cardinal fish, gobies, tilefish, fairy basslets, fairy and flasher wrasses,and sometimes other species butterflyfish.
It may not do well with large or aggressive fish. Seeing it dart into hiding is a good indication that it is feeling threatened and the situation may need to be remedied with one of the fish being removed. The large and rather territorial angelfish like Pomacanthus and Holacanthus should be avoided, as should most damselfish species. Small but very territorial fishes like dottybacks should also be avoided as well as such fish as basses or scorpionfish, even if they are small.
A positive to keeping them in a reef tank is that there are some individuals that may help rid the reef of those pesky Aiptasia species.
- Venomous: No
- Temperament: Peaceful - An occasional adult may become aggressive.
- Compatible with:
- Same species - conspecifics: No - It is territorial and will be aggressive towards other members of its own kind.
- Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Safe
- Semi-Aggressive (anthias, clownfish, dwarf angels): Monitor
- Aggressive (dottybacks, 6-line & 8-line wrasse, damselfish): Threat
- Large Semi-Aggressive (tangs, large angels, large wrasses): Monitor
- Large Aggressive, Predatory (lionfish, groupers, soapfish): Threat
- Slow Swimmers & Eaters (seahorses, pipefish, mandarins): Monitor
- Anemones: Monitor
- Mushroom Anemones - Corallimorphs: Monitor
- LPS corals: Threat
- SPS corals: Monitor
- Gorgonians, Sea Fans: Monitor
- Leather Corals: Safe
- Soft Corals (xenias, tree corals): Monitor
- Star Polyps, Organ Pipe Coral: Monitor
- Zoanthids - Button Polyps, Sea Mats: Monitor
- Sponges, Tunicates: Monitor
- Shrimps, Crabs, Snails: Monitor
- Starfish: Monitor
- Feather Dusters, Bristle Worms, Flatworms: Threat
- Clams, Scallops, Oysters: Monitor
- Copepods, Amphipods, Mini Brittle Stars: Threat
No sexual difference is noted for this species. Butterflyfish species studied up to this time indicate that these fish are gonochoristic, meaning that each fish is either a male or a female and they do not change sex.
The Copperband Butterflyfish has not been cultivated in captivity. In the wild butterflyfish are pelagic spawners that release many tiny eggs into the planktonic water column where they float with the currents until they hatch. Once hatched the fry are in a post-larval where their body, extending from the head, is covered with large bony plates.
Marine butterflyfish have not reportedly been spawned successfully in captivity. There are, however, reports of some success in rearing wild collected larvae of some of the corallivorous butterflyfish. It is hoped these captive reared fish will be adapted to accept aquarium foods, and thus broaden the species selections that can be sustained in captivity. For more information see, Marine Fish Breeding: Butterflyfish.
- Ease of Breeding: Unknown
The Copperband Butterflyfish are generally hardy and problems with disease are reduced in a well maintained aquarium. Any additions to a tank can introduce disease, so it's advisable to properly clean or quarantine anything that you want add to an established tank prior to introduction.
Diseases that marine Butterflyfish are susceptible to include Marine Ich(white spot disease), Marine Velvet, Uronema marinum, and Lymphocystis. Some can be treated successfully with medical care or copper drugs, but some species hate sudden changes of water including PH, temperature, or any drug treatment. In the wild a cleaner wrasse (Labroides sp.) will help them by taking parasites from their bodies, however these wrasses are extremely difficult to sustain in captivity. Alternative fish such as Neon Gobies (Gobiosoma spp.) can help them by providing this cleaning service in the home aquarium.
This species will often suffer from Lymphocystis and sometimes they suffer from "ich" (white spot disease) and other infectious diseases. Be sure to observe this fish closely when medicating it, so you can remove it if it shows signs of stress. For information about saltwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.
"I have kept more than seven specimens of 7-10cm in community fish tanks. Some of these beautiful butterflyfish would do fairly well for a period of time. But some of these refused any food offered and starved to death within a month, without any sign of other trouble." ...Hiroyuki Tanaka
The Copperband Butterflyfish commonly available at retailers. Most are smaller than 5 1/2 inches (14 cm), but juveniles less than 1 1/2 inches (3 cm) are rare. Most are moderately priced fish that are mainly shipped from the Philippines and Indonesia, they start at about $20.00 USD. Specimens from Australia cost a bit more, starting at about $50.00 USD.
- Animal-World References: Marine and Reef
- Chelmon rostratus (Linnaeus, 1758) Copperband butterflyfish, Fishbase.org
- Chelmon rostratus, The IUCN Red List of Threatened Species
- Robert M. Fenner, The Conscientious Marine Aquarist: A Commonsense Handbook for Successful Saltwater Hobbyists, TFH Publications, 2001
- Helmut Debelius, Rudie H. Kuiter, World Atlas of Marine Fishes, Hollywood Import & Export. Inc., 2006
- Scott W. Michael, Angelfishes & Butterflyfishes: Reef Fishes Series , Microcosm Ltd, 2004
- Mark Allen, Roger Steene and Gerald R. Allen, A Guide to Angelfishes and Butterflyfishes , Odyssey Publishing, 1998
- Dr. Warren E. Burgess, Dr. Herbert R. Axelrod, Raymond E. Hunziker III, Dr. Burgess's Atlas of Marine Aquarium Fishes, T.F.H Publications inc., 1990
- Roger Steene, Gerald R. Allen, Hans A. Baensch, Butterfly and Angelfishes of the World, Volume 1, John Wiley & Sons, 1980
- M. Allen, R. Steene, G. R. Allen, A Guide to Angelfishes and Butterflyfishes , Odyssey Publishing, 1998
- Warren E. Burgess, Butterflyfishes of the World, TFH Publications,1978
- Linnaeus, C., Systema Naturae. ed. Decima. Systema Naturae sive regna tria naturae, systematicae proposita per classes, ordines, genera et species, cum characteribus, differentiss, synonymis, locis, etc. Editio Decima, reformata, Holmiae, 1758. Regnum animale, ⅱ, 842pp.