In an attempt
to break new ground and provide readers with some exclusive
material on the amazing butterflyfishes, Marine World, in conjunction
with Vincent Hargreaves, has had a team of divers spend a week
in Western Australia looking for rare specimens to photograph.
Not only does this series of articles include some amazing photographs
of some of the world’s best underwater photographers but
we are also pleased to be the first magazine to report on a
new species of butterflyfish which is currently being described.
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There are currently 125
valid species in this family and I intend to describe and illustrate
all of them over the coming months. The series should prove
to be a valuable reference work for the future, so you should
keep the copies of Marine World safe in a binder! In this article,
the first 12 species are described. If any reader has a photograph
of an unusual species of butterflyfish, or would like to identify
the species they have in their tank, I can be contacted by e-mail
at atollreef@aol.com. General
information
Butterflyfishes belong to the family Chaetodontidae. This encompasses
a group of fishes with striking characteristics. Generally,
they are disc-shaped and strongly compressed with deep bodies,
and high backs. The snout is often elongated and the mouth is
armed with tiny brush-like teeth (hence, Chaetodon = bristle
teeth). There is a single, continuous dorsal fin without a notch
between the spinous and soft parts. Butterflyfishes rate amongst
the most colourful fishes on the reef. Most species have a black
vertical bar running down the head and through the eye. It is
thought that this serves to confuse predators. This, along with
a prominent black ‘eye spot’ that many species exhibit,
serves to mislead an attacking fish into thinking it is aiming
for the head when, in fact, it is the tail. The ruse is then
complete when the butterflyfish darts away in a totally unexpected
direction.
Adult fishes are often seen on the reef during the day, usually
singly or in pairs. Juveniles, on the other hand, are frequently
encountered in small groups of up to twenty individuals. At
night, many assume a shadowy night time colouration and retire
into a nearby crevice or hole between the corals. This hiding
place is arbitrary and is simply the nearest safe haven at nightfall.
All of these species are essentially shallow water fishes that
inhabit reef shallows, lagoons, back-reef areas and coral pools.
Some may venture down to depths of over 100 feet (30 metres)
but this is not common. The exceptions to this include the Lemon
butterflyfish (Chaetodon miliaris), which is found on the reefs
of the Hawaiian Islands. Using a submersible, scientists found
this species at depths of over 830 feet (250 metres).
Their diet is very varied but usually consists of benthic algae
along with small anemones, coral polyps, polychaetes, crustaceans
and various minute invertebrates and plankton. Their elongated
snouts are specifically developed to enable them to forage for
food between the coral heads and rocks. In a single feeding
foray, a pair of fish can cover a vast area of the reef.
Knowledgeable readers will notice that I have omitted the so-called
Chaetodon andamanensis Kuiter & Debelius, 1999. Until DNA
analysis proves otherwise, I regard this is as an invalid species
and I place it in the synonymy of Chaetodon plebeius. My reasons
for doing so will become apparent when C. plebeius is discussed
in a later article.
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Chaetodon adiergastos Seale,
1910
Common name
Philippine butterflyfish
Natural habitat:
Around soft coral on coral reefs, usually in pairs or small groups,
in the Indo-West Pacific from the Ryukyu Islands to Australia and
including the Philippine Islands and Indonesia.
Maximum adult size 6.3 inches
(16cm) Description
The body colour is white with thin diagonal brown stripes on
the sides. The dorsal, anal and pelvic fins are yellow and the soft
portions of the dorsal and anal fins have brownish-black margins.
The caudal fin base is yellow, which extends roughly half its length.
After this there is a narrow brownish black bar leaving the rest of
the fin transparent. Young fish have a black ocellus that fades with
age. There is a broad black eye bar and a large dark blotch on the
nape. Aquarium suitability
This is a surprisingly easy butterflyfish to keep in an aquarium,
but unfortunately it is not often imported. If it is housed in a reef
tank, it will not do any damage to stony corals once it has got used
to its normal aquarium feeding regime. Despite this, it should not
be housed with arborescent forms of soft coral, such as Nephthea and
Alcyonium species. 
Chaetodon argentatus Smith
& Radcliffe, 1911
Common names Black pearl butterflyfish,
Silver butterflyfish
Natural habitat
Central Indo-Pacific to the Indo-West Pacific in pairs or
small aggregations in areas of dense coral growth.
Maximum adult size: 8 inches
(20cm)
Description
The body is laterally compressed and silvery white in color, with
some scales edged in black. A black bar is present through the eye
but is often indistinct. A second bar from the dorsal to the pectoral
base is clearer. A wide mid-body bar ends halfway down the side and
the fourth bar, much clearer defined, extends across the caudal base
from the soft dorsal to soft anal fins. The belly is often bright
yellow in juveniles and there are two dark bars on the tail.
Aquarium suitability
Does quite well in a large enough aquarium and is one of the hardier
species of Butterflyfishes. It is sometimes inclined to be aggressive
towards its smaller relatives. Most foods are accepted but a particular
favourite is frozen adult brine shrimp. 
Chaetodon assarius Waite,
1905 Common names
West Australian butterflyfish, Western
butterflyfish. Natural
habitat
In small schools on rocky reefs and sandy seagrass beds of the Southeast
Indian Ocean. It is endemic in Western Australia from the Perth area
to Shark Bay.
Maximum adult size
5.1 inches (13cm)
Description
This is a close relative of Chaetodon guentheri from Southeast Australia.
There is a broad white-edged black bar through the eye and the body
is Tan or white in juveniles. The dorsal fin is dusky yellow and has
a white-edged black ocellus on the soft portion that reduces in size
with age. The base of the anal fin and caudal peduncle are dark ochre
and the anal fin has a black submarginal border. There are five narrow
bars that run vertically from the base of the spinous dorsal fin to
the mid-body region roughly level with the eye. The pelvic fins are
translucent or white. Aquarium
suitability
Not often imported into Europe or the United States. Nevertheless,
this is a relatively easy fish to keep and feed. It should be provided
with a tank containing plenty of live rock on which it can graze.
Its natural diet consists of plankton, algae and the tiny invertebrates
that are ingested with this. This is one of the butterflyfishes that
can be kept in a mature reef tank.

Chaetodon aureofasciatus
Macleay, 1878
Common names
Golden butterflyfish, Golden-striped
butterflyfish
Natural habitat
Indo-West Pacific from New Guinea, Australia from the Great Barrier
Reef to Western Australia and Melanesia. Usually encountered singly
or in pairs in inshore reefs and coastal areas.
Maximum adult size
5 inches (12.5cm)
Description
The closest relative to this fish is C. rainfordi with which it
bears many similarities. In this case though, there are no bars
on the body and the median and pelvic fins are bright yellow. Like
C. rainfordi, there is a black-edged orange bar through the eye,
although this is not joined at the nape.
Aquarium suitability
This fish is not suitable for a reef tank because its natural diet
comprises coral polyps as well as algae and other benthic invertebrates.
Although it is capable of withstanding high changes in the specific
gravity of seawater (it is often encountered in river mouths and
estuaries) it is difficult to get to feed. Live blood worms (Enchytrae)
seem the best bet at the start, followed by frozen ones from your
pet supplier. After that, it’s only a matter of time before
they accept other foods.
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Chaetodon auriga
Forsskål, 1775
Common names
Threadfin butterflyfish, Golden butterflyfish,
Threadfin, Diagonal butterflyfish
Natural habitat
Entire Tropical Indo-Pacific and Red Sea in back reef areas, lagoons
and reef channels. They are found singly or in pairs in the reef
shallows to depths of up to 35 feet (10 metres).
Size
8 inches (20cm)

Description
The Threadfin butterflyfish is common throughout its natural range
and is easily befriended by divers offering morsels of food. Adult
specimens have a long dorsal filament. Specimens from the Red Sea
lack the ocellus on the soft dorsal fin and the dorsal filament
is shorter. Young fish have a bright yellow dorsal area, which extends
down across the caudal peduncle onto the soft portion of the anal
fin.
Aquarium suitability
This is one of the easiest of all the Butterflyfishes to
keep. The aquarium should be large enough and have plenty of hiding
places into which it can retire at night. Provide good water quality
and an assortment of frost foods in its diet and this fish will
flourish.

Chaetodon auripes
Jordan & Snyder, 1901
Common names
Oriental butterflyfish, Gold butterflyfish
Natural habitat
Rocky reefs from Japan to Taiwan in coastal areas, sometimes
where the water temperature is as low as 50o F (10o C.)
Maximum adult size
8 inches (20cm)
Description
Young fish have a black ocellus on the sort dorsal fin,
which disappears with age. The snout is silver to bluish-grey and
there is a black eye band present. Behind this eye band there is
a broad white bar that extends from the nape to the base of the
opercle. This white bar has caused much confusion in the past between
this species and C. collare. However, C. auripes has a yellow-gold
body colour with narrow horizontal stripes. The caudal fin is yellow
with a submarginal black bar and the soft portions of the dorsal
and anal fins have black margins with white sub-marginally.
Aquarium suitability
Although this species is seldom imported it settles down
well to aquarium life. It is robust and eager to accept most foods
that are offered once it feels happy with its new surroundings.
In the wild, it feeds on benthic invertebrates such as polychaetes
and coral polyps. In a tank environment though, it will accept krill,
mysid shrimp, Artemia, frozen plankton and finely chopped shellfish.

Chaetodon austriacus
Rüppell, 1836
Common name
Blacktail butterflyfish
Natural habitat
Found in areas of dense coral growth throughout the Western
Indian Ocean and Red Sea. Juveniles form small aggregations in and
around a single coral head.
Maximum adult size
5.1 inches (13cm)
Description
Easily confused with C. melapterus and C. trifasciatus. However,
in this case the anal and caudal fins are black with yellow margins
in adults. Juveniles are less colourful than their adult counterparts.
They have a large yellow-edged ocellus on the caudal peduncle. The
dorsal fin is white with a submarginal border of black in the soft
dorsal portion. There is a black bar through the eye and a second
bluish-grey bar from the dorsal base to the lower angle of the operculum.
The body colouration is predominantly yellow with narrow, bluish
stripes that are intense dorsally, becoming indistinct ventrally.
A broad horizontal daub of black is present in the third stripe
towards the posterior dorsal region.
Aquarium suitability
Feeds almost exclusively on coral polyps, therefore it is
difficult to get to feed in an aquarium. Occasional specimens have
been coaxed onto alternative aquarium foods and these do well. However,
this is the exception, rather than the rule.

Chaetodon baronessa
Cuvier, 1829
Common name
Triangular butterflyfish
Natural habitat
Western Pacific to central Indo-Pacific. It is common on
the Great Barrier Reef and is usually encountered in pairs in reef
shallows.
Size
6 inches (15cm)
Description
The body carries a series of chevron markings and the margins
of the dorsal, anal and ventral fins are chrome yellow. There are
three vertical bars on the head and the snout is often dull orange.
It is easily confused with Chaetodon triangulum. However, C. baronessa
lacks the yellow-edged triangular mark on the tail.
Aquarium suitability
Although this species is reported to be quite difficult to
keep, the fat and healthy specimen shown here had, at the time this
photograph was taken, already spent two and a half years in an aquarium.
Its diet consisted of a variety of frozen foods supplemented with
flake food and it did little if any damage to the live corals in
the aquarium. Nevertheless, this species will not tolerate high
nitrate levels.
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Chaetodon bennetti
Cuvier, 1831
Common name
Bennett’s butterflyfish
Natural habitat
Juveniles are found in reef shallows and lagoons, sometimes
in small groups of four or five individuals. Adults are usually
encountered singly or in pairs on outer reef slopes.
Maximum adult size
7 inches (18cm)
Description
The overall body colouration is bright yellow and there
is a blue-edged black bar through the eye. Juveniles have a white-edged
black lateral ocellus below the spinous dorsal fin. As the fish
grows, the white margin turns to deep blue. Two broad blue lines,
which are widely separated, curve upwards from the base of the anal
fin and finally converge at the upper angle of the gill cover. A
dull orange bar is present across the caudal peduncle.
Aquarium suitability
This species feeds exclusively on coral polyps and is extremely
difficult to feed in captivity. Limited success has been achieved
by spreading chopped squid and krill on live rock, in order to induce
the fish to feed. Nevertheless, this is perhaps one of the species
that is better left on the reef.

Chaetodon blackburnii
Desjardins, 1836
Common names
Rayed butterflyfish, Brownburnie
Natural habitat: Coral reefs on outer reef slopes in the Western
Indian Ocean from Kenya to Mauritius and Madagascar.
Maximum adult size
5.1 inches (13cm)
Description
Juveniles have dark brown bodies with bright yellow on and
behind the operculum. Adults are somewhat lighter in colour and
the opercular region is often brownish-yellow. There is a dark eye
bar present and the caudal fin is white with a translucent margin.
Six or more diagonal bars adorn the sides of the body, but these
are not so readily apparent in juveniles. The dorsal and anal fins
are brownish-black and the pelvic fins are bright yellow.
Aquarium suitability
Not often imported into Europe, but in the United States
this species has grown in popularity because of its hardiness. Although
it is not the most colourful of all the butterflyfishes, it makes
up for this by its eagerness to feed on most foods that are offered.
An excellent aquarium fish!

Chaetodon burgessi
Allen & Starck, 1973
Common name
Burgess’ butterflyfish
Natural habitat
On reef drop-offs where there is an abundance of gorgonians
and black coral throughout the Western Pacific from Indonesia and
the Philippines to Palau.
Maximum adult size
5.5 inches (14cm)
Description
The body is white with three broad, brownish-black diagonal
bars. The first of these is the eye bar. A second runs from the
nape to a point just below and behind the pectoral fin. The third
bar runs from the base of the third dorsal spine to the anal fin
leaving the dorsal fin, caudal peduncle and posterior portion of
the anal fin deep brownish-black. The tail is white or translucent
and the dorsal fin has a narrow white margin.
Aquarium suitability
With a bold attitude and a great appetite, Chaetodon burgessi
is probably one of the hardiest butterflyfishes in captivity. It
is not common but soon settles down to aquarium life.

Chaetodon capistratus
Linnaeus, 1758
Common name
Mock-eye butterflyfish, Four-eye
butterflyfish
Natural habitat
Widespread in the Caribbean and the Gulf of Mexico in a
variety of habitats around coral reefs.
Maximum adult size
5 inches (13cm)
Description
A very attractive species with delicate colouration. There
is a dark bar through the eye and a series of thin, chevron-formed
bars along the body. The nape, snout and ventral regions are yellow
and there is a large, white-edged black ocellus forward and above
the caudal peduncle.
Aquarium suitability
Despite some conflicting accounts from other aquarists and
aquarium book authors, this fish is quite easy to keep and hardy
once it is settled down to tank life. All foods that are offered
will be readily accepted
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