Butterflyfish - Chaetodontidae

Family variety

Butterflyfish are a large family, with over 100 species. Markings, patterns and fin shape can vary greatly between species, but overall body shape, colouration and behaviour are usually similar across the family.

Size

Individuals are generally medium sized fish ranging from the smallest the 12cm long Eight Banded Butterflyfish (Chaetodon octofasciatus) to the 30cm Lined Butterflyfish (Chaetodon lineolatus) the biggest in the family.

Behaviour

Butterflyfish are benthic, living on coral reefs. Depending on the species they either swim in pairs close to the reef or in schools over the reef - forming constantly moving colourful clouds.

They tend to be wary and often change direction suddenly, resulting in a skittish swimming styleand are quick to seek shelter when threatened.

Distribution

Butterflyfish can be found throughout tropical waters. Some reefs have just a couple of species, others can have up to 20 different resident Butterflyfish species.

Habitat

Most Butterflyfish prefer shallow healthy reefs. Some plankton feeding species prefer areas with faster currents where they form large schools in mid-water.

Diet

Many Butterflyfish feed on coral polyps or algae, while some species are plankton feeders, relying on the tiny microscopic creatures living in the water.

Reproduction

Many species pair for life and spend the majority of time with their partners. They are known to gather in large schools in mating season, rising together above the reef and releasing eggs and sperm mid water.

Defences

Many of the butterflyfishes' characteristic stripes and markings are designed to provide camouflage and confuse predators into attacking their tail end rather than their head. They are also very agile & fast swimmers, helping them to escape quickly. Their small size also allows them to hide in small cracks & crevices out of the reach of larger predators.

Threats

Butterflyfish are not generally considered good eating fish, so are rarely over fished. Their greatest threat is from loss of habitat and the overall decline of the world's reefs.

Did You Know?

Butterflyfish are a good indicator species of the health of a reef.

A healthy reef will have many Butterflyfish, while one that is suffering may see a rapid decline in numbers.

Intro

Some of the most colourful and graceful of all tropical fishes, the Butterflyfish family encompasses some of the reefs most famous inhabitants.

Many species pair for life and are seen swimming together in perfect synchronisation. They spend much of their time flitting over shallow coral reefs, showing off their vibrant markings and incredible patterns.

These shy fish will only normally allow a close look at their dazzling livery if you approach slowly and quietly.

Popular species 1

Coral Beakfish

(Chelmon rostratus)

Often observed in pairs, this striking butterflyfish has beautiful orange bands and a long pointed snout.

Popular species 2

Threadfin Butterflyfish

(Chaetodon auriga)

Easily identified by the long trailing filament on the rear dorsal fin. Can grow to 23cm in length. Usually observed in pairs feeding on the polyps of soft and hard corals. Their range is from the Red Sea to Australia.

Popular species 3

Longfin Bannerfish

(Hemiochus diphreutes)

Bannerfish are readily distinguished from other Butterflyfish by their incredibly long, trailing dorsal fin.

They are sometimes confused with Moorish Idols - though from a different family, both fish can look very similar at first glance. On closer inspection, the head shape is very different. The Longfin Bannerfish has a yellow tail but the Morish Idol's is black.

Popular species

There are numerous species of Butterflyfish to look out for on a dive. Here are a few popular species.

Related Dive Spots

Komodo & Rinca

Phuket & Phi Phi

Bohol

FACTFILE

SPECIES: >100

SIZE RANGE: 12-30 cm

DISTRIBUTION:

Found throughout tropical waters.

HABITAT:

Shallow healthy reefs. Some plankton feeding species prefer mid-water in current.

THREATS:

Greatest threat is loss of habitat.

Identification tips

Butterflyfish have very thin disk shaped bodies that very little drag when swimming through the water.
Many Butterflyfish have a false eye spot near their tail to confuse predators.
Butterflyfish usually have a dark stripe through their eye to disguise their heads.
Many species have a streamer like extension to the dorsal fin.
Butterflyfish are very colourful with a wide variety of patterns and markings. Many species use a combination of yellow, black and white stripes.