The butterfly fish are a group of tropical marine fish belonging to the family Chaetodontidae. There are approximately 129 species of butterfly fish that are mostly found on the reefs of the Atlantic, Indian, and Pacific Oceans. Butterflyfish look like smaller versions of angelfish (Pomacanthidae), but lack preopercle spines at the gill covers.
Thanks to their beautiful colors and patterns and docile personality, many butterfly fish are popular aquarium fish, and they are often found as pets. The name Chaetodontidae is a combination of two Ancient Greek words: chaite, meaning hair, and odontos, meaning tooth. This is probably a reference to the rows of brush-like teeth in these fishes mouths.
This Chaetodontidae family should not be confused with the freshwater butterfly fish (also known as the African butterfly fish). Endemic to the West African region, the freshwater butterfly fish belongs to an entirely different order. The freshwater butterfly fish is more closely related to other African fish in the order of Osteoglossiformes.
Butterfly Fish Characteristics
Butterfly fish are closely related to angelfish and both groups are collectively known as coralfish. Butterfly fish are small fish and most do not exceed 12 to 22 centimetres (94.7 to 8.7 inches) in length. The largest of the species is the lined butterfly fish (Chaetodon lineolatus) and the saddle butterfly fish (Chaetodon ephippium) which grows to 30 centimetres (12 icnhes) in length. Butterfly fish are, in general, sexually monomorphic (meaning males and females look alike), although occasionally males have been found to be larger than females.
These fish are named for their brightly colored and strikingly patterned bodies, in shades of black, white, blue, red, orange and yellow. Some species are dull in color. Like patterns seen on butterfly wings, many of the species have eyespots on their flanks and dark bands across their eyes. Their coloration makes them popular aquarium fish, and as they are relatively small, they don’t need a large fish tank to house them.
Butterfly fish have uninterrupted dorsal fins with tail fins that may be rounded or truncated, but are never forked. The dorsal fin on the back sometimes features sharp spines which provide a defense against potential predators.
Their bodies are deep and laterally compressed, which allows them to slip between rocky outcroppings and reef crevices. This, combined with their bright colors, has lead many to believe they are intended for interspecies communication.
These fish also have a protruding snout, varying in length depending on the species, that is tipped with a small mouth. This extended snout allows them to reach inside cracks and holes to feed small organisms hiding within.
Butterfly Fish Species
There are around 129 species of butterfly fish and 12 genera. Some of the best known species of butterfly fish include:
Auriga Butterfly Fish
Also known as the threadfin butterfly fish, this species has a wide Indo-Pacific distribution and is black, white and yellow in color.
Blacknosed Butterfly Fish
This species is found in the East Pacific and has a yellow body, a white face, and black markings around the upper fin and parts of the face. It is also known as the barberfish.
Bluecheek Butterfly Fish
This species is found in the northwestern Indian Ocean and is mainly yellow with a blue, mask-like pattern around its eyes and cheek.
Bluestripe Butterfly Fish
This species is found in the waters surrounding the Hawaiian Islands and is common in shallow water reefs. They are vibrant yellow with thin blue stripes running diagonally over the body from the snout.
Copperband Butterfly Fish
This species is endemic to the Pacific and Indian Oceans. It has a particularly long snout and alternating stripes of white and orange around the body. It is also known as the orange stripe butterfly, beaker coralfish or beaked butterfly fish.
The Copperband Butterfly Fish (Chelmon rostratus) have a ‘false eye’ towards the back of the dorsal fin and can grow up to about 8 inches (20 centimetres) in length. Primarily carnivorous, they feed on a variety of marine foods, including brine and mysis shrimp. Copperband Butterfly Fish will also eat aiptasia (glass anemones).
In captivity, Copperband Butterfly fish are very sought-after mostly for what it can do rather than for its looks. Copperband Butterfly Fish are known to consume aiptasia, the pest anemones which are not welcome in tanks.
Falcula Butterfly Fish
Also known as the sickle butterfly fish, this species grows up to 8 inches. They are white, gray, black and yellow and are found in the Indian Ocean.
Foureye Butterfly Fish
This species (Chaetodon capistratus) is native to the Atlantic Ocean from Massachusetts to South America. It has a white and blue body with darker stripes emanating out from the center.
It is a butterfly fish of the family Chaetodontidae. These fish are found among tropical reefs around the world and particularly in the Indo-Pacific oceanic region.
The foureye butterfly fish is also found in the Western Atlantic from Massachusetts, USA and Bermuda to the West Indies and northern South America.
Foureye butterfly fish are deep-bodied and laterally compressed, with a single dorsal fin and a small mouth with tiny, bristle like teeth. The foureye butterfly fish mates for life and therefore they will often be seen in pairs.
Foureye butterfly fish get their name due to a large, dark spot on the rear portion of each side of the body. This spot is surrounded by a brilliant white ring resembling a false eye. A black, vertical bar on the head runs down the true eye, making it more nondescript and may result in a predator confusing the back end of the fish for the front end. The four-eye butterfly fishes first instinct when threatened is to flee, putting the false eye spot closer to the predator than the head. Most predators aim for the eyes and this false eye spot tricks the predator into thinking that the four-eye will flee tail first.
When escape is not possible, the foureye butterfly fish will sometimes turn to face its aggressor, head lowered and spines fully erect. This may serve to intimidate the other animal or may remind the predator that the butterfly is much too spiny to make a comfortable meal.
Foureye butterfly fish usually frequent shallow inshore waters, where they feed on a variety of crustaceans and coral polyps.
The foureye butterfly fish is known for its uncanny ability to swim in and around coral heads and reefs. The fish is able to find its way through the most intricate passages by swimming on its side or even upside down.
Fourspot Butterfly Fish
This species has a yellow underside, black dorsal fin and two white spots on either side. It is found in the Pacific Ocean.
Klein’s Butterfly Fish
Also known as the blacklip butterfly fish, this species is mostly golden-yellow, and has wither a black or black and blue eye band. It is an Indo-Pacific species of reef habitats.
Lemon Butterfly Fish
This species is mainly yellow with dark spots which form vertical stripes. It has black line through its eyes and yellow fins. It is also sometimes known as the milletseed butterfly fish. It is endemic to the Hawaiian Islands
Lined Butterfly Fish
This species has a wide range from the Red Sea to South Africa and as far east as southern Japan and Hawaii. It has a white body with thin black vertical lines coming down from a yellow dorsal fin. It is the largest of the species.
Pearlscale Butterfly Fish
This species can grow up to 6 inches and has a pearly white body with a net-like black pattern. It is found in the West Indian Ocean.
Pebbled Butterfly Fish
Also known as the multiband butterfly fish, this species is a small fish and has a creamy white body, with 5 or 6 tan lines running vertically. It is located in Hawaii.
Pyramid Butterfly Fish
This species is yellow and white in color and is native to central Indo-Pacific.
Raccoon Butterfly Fish
This species (Chaetodon lunula) is a yellow-orange color and has black patches around the eyes, which gives it it’s name. They are found in Indo-Pacific regions.
This fish is also known as crescent-masked or lunule butterfly fish. It is found in the Indo-Pacific oceans from East Africa and also in the southeast Atlantic from East London, South Africa. This fish is usually found at depths down to 30 metres.
The Raccoon butterfly fish can grow up to lengths of 20 centimetres. The Raccoon butterfly fish is a nocturnal species that usually swims in pairs or small groups in warm, shallow reef flats of lagoon and seaward reefs. Juveniles occur among rocks of inner reef flats and in tide pools. Adults feed mainly on nudibranchs (soft-bodied, shell less marine mollusks), tubeworm tentacles (worm-like invertebrates) and other benthic invertebrates including algae and coral polyps.
The Raccoon butterfly fish is generally not aggressive towards other fish, with the exception of lionfish and triggerfish. In captivity, the typical life span of a Raccoon butterfly fish is 5 to 7 years.
Reproduction is oviparous (animals that lay eggs, with little or no other embryonic development within the mother. This is the reproductive method of many fish, amphibians and reptiles, all birds, the monotremes and most insects and arachnids), with pairs forming during breeding.
Saddleback Butterfly Fish
This species has a large black “saddle” surrounded by a white border on the upper rear of the body and dorsal fin. It is found in the Indian Ocean.
Teardrop Butterfly Fish
Growing up to 8 inches long, this species has a white base which blends into yellow, a black vertical stripe through its eyes and a large black eyespot on its upper side. It is found in the Indo-Pacific region.
Tinkers Butterfly Fish
Also known as the Hawaiian butterfly fish, this species has a white body with black spots and a yellow and orange face. It is found in Hawaii.
Yellow Longnose Butterfly Fish
This species (Forcipiger longirostris) is found in the Indo-Pacific area. It is notable for its yellow body and long nose. It can grow up to 9 inches long.
The Longnose Butterfly fish, has a very flat body, which allows it to dart in and out of narrow escape routes on the reef, and a very long snout. It is a small fish only growing to up to 6 inches (22 centimetres) long. Longnose Butterfly fish have long thin spines in their dorsal fins (back fins).
Most butterfly fish have an eye band or dark line on their body that runs across the eye. This band masks their eye and confuses predators whose attention is focused on a false eyespot or spot on the fishes tail.
The bright colors of the longnose butterfly fish help it to camouflage in the reefs. Juvenile butterfly fish look different, and in many instances, completely different from their adult form. As they mature, their colors, patterns and even face shape changes.
Their bright colors are muted while they rest at night helping them to hide in the coral and inside reef caves from predators. Longnose Butterfly fish can be found in warm waters on coral reefs in the Indo-West and Central Pacific. In Australia, it is known from waters of north-western Western Australia and from the northern Great Barrier Reef. Longnose Butterfly fish either swim alone or in groups of up to five fish on seaward reefs or reefs near the open ocean and in lagoons at depths of 3 to 380 feet (1 to 114 metres).
Longnose Butterfly fish are diurnal or active during the day. A fussy eater, the Longnose Butterfly fish preys on tiny animals that hide among sea urchin spines and in coral holes and crevices. Their jaws contain slender brush-like teeth which enable them to easily scrape prey off the reef. Longnose butterfly fish eat a wide variety of creatures like fish eggs, shrimp, worms, sea urchins, sea stars, coral polyps and also algae.
Longnose Butterfly fish reproduce with one partner for life and are pelagic spawners, gathering in groups in areas where the fertilized eggs will be taken by the currents. The eggs float in the epipelagic zone or the zone in the open ocean near the surface until the larvae hatch. The larvae live in the plankton layer up to two months. When they reach a certain size, they swim down at night to a reef and join that ecosystem. While floating around, larvae are covered in bony armour, often with serrated or saw-like spines sticking out.
Yellow tail butterfly fish
This species (Chaetodon xanthurus) is a small fish which grows to around 14 centimetres in length. The main part of its body is white with a black reticulated pattern on the sides and an orange colored band towards the back of its body. Because of this particular pattern, it is sometimes referred to as the ‘Pearlscale butterfly fish’.
The Yellow tail butterfly fish has a black spot with a white edge on its nape. It is distributed in Indonesia and the Philippines, north to the Ryukyu Islands in the Western Pacific and is encountered normally along the external reef where it has a maximum depth range of 6 – 50 metres.
Found around stag horn corals, the Yellow tail butterfly fish is the only member of the family with a crosshatch pattern of dark lines on the sides. It is generally seen below 15 metres depth and occurs singly or in pairs. It feeds on small benthic invertebrates and algae.
The Yellow tail butterfly fish is easily confused with the species Atoll Butterflyfish (Chaetodon mertensii) which can be distinguished by the reticulated color pattern on the sides and by the nape spot with a clear edge.
Butterfly fish have an average lifespan of between 5 and 10 years.
Butterfly fish eat mostly small invertebrates such as sponges, worms and plankton. They’ll also eat coral polyps, algae and sea anemones. They feed during the day, at the bottom layer of the seabed.
Butterfly fish are diurnal animals, which means they are active and feed during the day and rest on the coral during the night. At night, butterfly fish hide in reef crevices and their colors can fade to blend and avoid predation.
The smaller species of butterfly fish tend to stay in groups, whereas the larger species are usually solitary or swim with their mating partner, with whom they mate for life. The butterfly fish relies on its sight to find prey and communicate with others.
Butterfly fish are specific about the time of year that they mate; in the tropics, the spawning season usually peaks in winter or early spring, but in temperate climates, the spawning season takes place in the summer.
When the female is ready to mate, her stomach becomes swollen with eggs. The male will come up from behind and gently nudge her abdomen with its snout, and they will release the eggs and sperm together, creating a white cloud in the water. Some males without a mate may swim in and quickly add his sperm to the cloud!
Gestation is only 28 to 30 hours. Butterfly fish play no part in raising their young and instead, the young have a unique larval stage in which they develop a plate of bony armor over the head to protect themselves. This plate eventually extends outward along the back to form spines, which are eventually absorbed into the body.
The young butterfly fish enters a juvenile stage when it has reached the size of a coin, during which period it exhibits different color patterns from its adult form. Juveniles will live within small tidal pools or shallow areas temporarily before moving to the corals.
Butterfly fish form monogamous pairs for at least three years and sometimes even their entire lives. They reach sexual maturity at around a year old.
Location and Habitat
Butterfly fish are mostly found in the coral reefs of the Atlantic, Indian and Pacific Oceans, in temperate, tropical and subtropical waters. The greatest concentration of species is found in a stretch of Pacific territory between Australia and Taiwan. Only four species occur in the Eastern Pacific and 13 in the Atlantic Ocean.
Their preferred habitat is the shallow warm water less than 65 feet deep near shores or estuaries, but a few species reside in deep water habitats up to 650 feet. They are well adapted to life in coral reef systems, though a few species also inhabit seagrass beds, lagoons, and mudflats. Young butterfly fish may occupy different areas than adults, such as tidal pools, boulder reefs and shallow areas without coral.
The exact population of the butterfly fish is unknown, but it is one of the most most common types of coral reef fish in the world. The species is listed as least concern on the IUCN Red List. That being said, they do face threats. The biggest threat to these fish is the destruction of the coral reefs.
The butterfly fish is never caught for food, but it is popular in the exotic pet trade. These animals can make good pets, but they have very specific requirements that can be demanding for the average fish owner.
The butterfly fish is preyed on by sharks, eels, snappers, and other large fish. Because they are very small, they have the ability to hide in small crevices around coral reefs. Many of the species have also evolved spines, armor, and toxins to deal with threats from predators.