Banded archerfish
Encyclopedia
The banded archerfish is a brackish water
perciform fish of the archerfish genus Toxotes
. It is silvery in colour and has a dorsal fin
towards the posterior end. It has distinctive, semi-triangular markings along its sides. It is best known for its ability to spit a jet of water to "shoot down" prey. Larger specimens may be able to hit prey 2 to 3 m (6.6 to 9.8 ) away. The banded archerfish may reach the displaced prey within 50 millisecond
s of its hitting the water.
The name (binomial as well as common) refers to Sagittarius
the archer, because of the unusual method banded archerfish use to capture prey. Banded archerfish are found in Indo-Pacific
and Oceania
n waters, generally in river mouths and mangrove
estuaries
. They move between fresh, salt, and brackish water over the course of their lifetime, though not to breed. Because of their markings and silvery colour, banded archerfish are sometimes kept as aquarium fish
, though they are difficult to care for and not recommended for most home aquaria.
in 1767
. Since then, several synonym
s (such as Labrus jaculatrix and Sciaena jaculatrix) and misspellings (Toxotes jaculator) have come into use.
Toxotes is Greek for "bowman" or "archer", and specifically refers to Sagittarius
. The species name jaculatrix is related to the English jaculate and means "thrower" or "caster" (of a dart or arrow). Both the common name and binomial name refer to the banded archerfish's habit of catching prey by shooting "arrows" of water through its mouth.
is yellowish-green and located towards the posterior end, and its base is shorter than that of the anal fin. The caudal fin is "dirty green" and about the same height until the point of attachment, where it becomes shallower. The anal fin is silver.
The body of the banded archerfish is oblong in shape and raised on the posterior side. The body is generally silver-white in colour, though varying colourations, such as yellow, have been observed. Four to six broad black bars may be present on the dorsal side. The first bar is found anterior to the operculum
, the bony plate covering the gills, and the second is found behind the operculum. The third bar is found below the origin of the dorsal fin, the fourth bar below the soft dorsal, and the fifth (if any) on the area between the anal fin and caudal fin (caudal peduncle). These bars become shorter as the fish ages. The lateral line
curves upwards at the area between the fourth and ninth lateral scales. Banded archerfish can reach a maximum length of 30 centimetres (11.8 in); however, average length is about 20 centimetres (7.9 in).
Banded archerfish have large eyes, which, unlike many other fishes, are positioned for binocular vision
. The head is slightly shorter than the body, with a distinctively pointed snout. Juveniles may be yellow-green to brown on the dorsal side and silvery on the ventral side. The juveniles' flanks are grey-green. Some banded archerfish have irregular yellow patches between their bands.
The possibility of sexual dimorphism
in banded archerfish has not been investigated.
) are sometimes grouped and sold together under the label "archerfish". However, the banded archerfish has four dorsal spines whereas largescale archerfish has five. The banded archerfish usually has four to five wedge-shaped bands, but largescale archerfish has six or seven spots and shorter bands in a regular, alternating pattern. Unlike the silvery banded archerfish, the largescale is sooty in colour. The banded archerfish may also be confused with the smallscale archerfish, Toxotes microlepis. These are more difficult to distinguish, but the most striking difference is in the last two bands. While both species have four or five wedge-shaped bands, those of the banded archerfish extend to the dorsal fin, whereas those of the smallscale archerfish do not; there are two spots on the dorsal fin separate from the main bar.
. In the daytime, they come to the surface to feed on floating matter. Their diet comprises plant matter and insects, which they are able to "shoot down". Banded archerfish are also able to capture prey by jumping out of the water and seizing it from low overhanging branches. Young archerfish form small schools while learning aim, increasing the chance that at least one shot will hit the target. Their diet also comprises underwater prey, including crustacean
s and small fishes.
s and can reach it within 50 ms of its hitting the water.
A study found that banded archerfish could be trained to hit moving targets at an accuracy rate of greater than 50%. According to this study, the ability to hit moving targets is a complex learned behaviour, and can be learnt from other members of the school. The study concluded that fish could shoot more accurately after observing other members of the school shooting.
The banded archerfish is able to hit targets with a high degree of accuracy, despite refraction
of light in the water. It is believed that they are able to achieve this level of accuracy by positioning their bodies to shoot from directly under the intended target. However, other studies have found that banded archerfish are able to achieve great accuracy even at angles, suggesting that they are somehow able to compensate for refraction. This may also suggest that banded archerfish are capable of three-dimensional tasks.
. There are reports that banded archerfish go to saltwater reefs to spawn, but these have not been confirmed. Archerfish lay 20,000 to 150,000 eggs at a time. Banded archerfish rarely breed in captivity.
The banded archerfish inhabits the Indo-Pacific
and waters off northern Australia, and less frequently those on the southern coast of Australia. It can be found from India
eastwards to the Philippine Islands, southwards to Australia, as well as in waters off the Solomon Islands
and the Indonesian Archipelago. It has been observed as far east as the New Hebrides (now known as Vanuatu
).
The banded archerfish occurs mainly in areas of brackish water. Mangrove
estuaries
are its primary habitat, though it occasionally moves upstream into freshwater rivers. It is associated with reefs and has been reported to occur near overhanging vegetation. While they may move between fresh and salt water
during their life cycle, they do not do so to breed.
of their mangrove swamp habitat and by pollution.
, including the banded archerfish, are kept as aquarium fish
. In aquaria, the banded archerfish can grow up to 25 centimetres (9.8 in) long. They swim at the top level of the aquarium. Banded archerfish can be kept in small groups of three to five; fish of the same size get along but fish that are larger may be aggressive towards those that are smaller, and even try to eat them. They may live from five to eight years in captivity, and occasionally nine or ten. Banded archerfish need warm water, usually between 25 and 30 °C (77 and 86 F). The aquarium should be large with middling amounts of plant growth and plenty of space for swimming. It should be 20 to 30 cm (7.9 to 11.8 ) deep.
Banded archerfish are generally not recommended for average home aquaria
despite their attractive appearance because they are difficult to care for and require special conditions. Banded archerfish prefer to shoot and capture live food rather than be fed flake food, making it problematic to feed them. They need brackish water as well as a tall canopy. In the wild they are able to jump out of the water to capture prey on overhanging branches; a tall canopy is required to prevent their jumping out of the aquarium. Banded archerfish should be kept in an aquarium with a volume of at least 45 gal, though a greater volume is preferred. Because of such difficulties in caring for banded archerfish, the species has not yet been successful in captivity.
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
perciform fish of the archerfish genus Toxotes
Archerfish
The archerfish are a family of fish known for their habit of preying on land based insects and other small animals by literally shooting them down with water droplets from their specialized mouths...
. It is silvery in colour and has a dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
towards the posterior end. It has distinctive, semi-triangular markings along its sides. It is best known for its ability to spit a jet of water to "shoot down" prey. Larger specimens may be able to hit prey 2 to 3 m (6.6 to 9.8 ) away. The banded archerfish may reach the displaced prey within 50 millisecond
Millisecond
A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....
s of its hitting the water.
The name (binomial as well as common) refers to Sagittarius
Sagittarius (astrology)
Sagittarius is the ninth astrological sign in the Zodiac, which spans the zodiac between the 240th and 269th degree of celestial longitude...
the archer, because of the unusual method banded archerfish use to capture prey. Banded archerfish are found in Indo-Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
and Oceania
Oceania
Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...
n waters, generally in river mouths and mangrove
Mangrove
Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...
estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
. They move between fresh, salt, and brackish water over the course of their lifetime, though not to breed. Because of their markings and silvery colour, banded archerfish are sometimes kept as aquarium fish
Aquarium fish
In fishkeeping, species of aquarium fish vary with the water chemistry of the aquarium.For species of fish found in particular types of aquaria, see:*List of brackish aquarium fish species*List of freshwater aquarium amphibian species...
, though they are difficult to care for and not recommended for most home aquaria.
Taxonomy and etymology
Toxotes jaculatrix were originally described by Peter Simon PallasPeter Simon Pallas
Peter Simon Pallas was a German zoologist and botanist who worked in Russia.- Life and work :Pallas was born in Berlin, the son of Professor of Surgery Simon Pallas. He studied with private tutors and took an interest in natural history, later attending the University of Halle and the University...
in 1767
1767 in science
The year 1767 in science and technology involved some significant events.-Agriculture:* Arthur Young publishes The farmer's letters to the people of England, containing the sentiments of a practical husbandman .....
. Since then, several synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
s (such as Labrus jaculatrix and Sciaena jaculatrix) and misspellings (Toxotes jaculator) have come into use.
Toxotes is Greek for "bowman" or "archer", and specifically refers to Sagittarius
Sagittarius (astrology)
Sagittarius is the ninth astrological sign in the Zodiac, which spans the zodiac between the 240th and 269th degree of celestial longitude...
. The species name jaculatrix is related to the English jaculate and means "thrower" or "caster" (of a dart or arrow). Both the common name and binomial name refer to the banded archerfish's habit of catching prey by shooting "arrows" of water through its mouth.
Description
Banded archerfish have four dorsal spines, 11 to 13 dorsal soft rays, three anal spines (of which the third is longest) and 15 to 17 anal soft rays. The first spine is always the shortest; the rays become shorter toward the posterior end. There are about 23 scales between the first dorsal spine and the posterior nostrils. Certain areas of the body are tinged green. The back of the fish is olive-green or brown. The dorsal finDorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
is yellowish-green and located towards the posterior end, and its base is shorter than that of the anal fin. The caudal fin is "dirty green" and about the same height until the point of attachment, where it becomes shallower. The anal fin is silver.
The body of the banded archerfish is oblong in shape and raised on the posterior side. The body is generally silver-white in colour, though varying colourations, such as yellow, have been observed. Four to six broad black bars may be present on the dorsal side. The first bar is found anterior to the operculum
Operculum (fish)
The operculum of a bony fish is the hard bony flap covering and protecting the gills. In most fish, the rear edge of the operculum roughly marks the division between the head and the body....
, the bony plate covering the gills, and the second is found behind the operculum. The third bar is found below the origin of the dorsal fin, the fourth bar below the soft dorsal, and the fifth (if any) on the area between the anal fin and caudal fin (caudal peduncle). These bars become shorter as the fish ages. The lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
curves upwards at the area between the fourth and ninth lateral scales. Banded archerfish can reach a maximum length of 30 centimetres (11.8 in); however, average length is about 20 centimetres (7.9 in).
Banded archerfish have large eyes, which, unlike many other fishes, are positioned for binocular vision
Binocular vision
Binocular vision is vision in which both eyes are used together. The word binocular comes from two Latin roots, bini for double, and oculus for eye. Having two eyes confers at least four advantages over having one. First, it gives a creature a spare eye in case one is damaged. Second, it gives a...
. The head is slightly shorter than the body, with a distinctively pointed snout. Juveniles may be yellow-green to brown on the dorsal side and silvery on the ventral side. The juveniles' flanks are grey-green. Some banded archerfish have irregular yellow patches between their bands.
The possibility of sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
in banded archerfish has not been investigated.
Comparison to other archerfish
The banded archerfish and its relative the largescale archerfish (Toxotes chatareusToxotes chatareus
Toxotes chatareus, sometimes known by the common names seven-spot archerfish or largescale archerfish, is a species of perciform fish in the archerfish genus Toxotes. They are usually no larger than but may grow up to . Unlike most archerfish, T. chatareus are sooty rather than silvery in...
) are sometimes grouped and sold together under the label "archerfish". However, the banded archerfish has four dorsal spines whereas largescale archerfish has five. The banded archerfish usually has four to five wedge-shaped bands, but largescale archerfish has six or seven spots and shorter bands in a regular, alternating pattern. Unlike the silvery banded archerfish, the largescale is sooty in colour. The banded archerfish may also be confused with the smallscale archerfish, Toxotes microlepis. These are more difficult to distinguish, but the most striking difference is in the last two bands. While both species have four or five wedge-shaped bands, those of the banded archerfish extend to the dorsal fin, whereas those of the smallscale archerfish do not; there are two spots on the dorsal fin separate from the main bar.
Diet and feeding
Banded archerfish are omnivorousOmnivore
Omnivores are species that eat both plants and animals as their primary food source...
. In the daytime, they come to the surface to feed on floating matter. Their diet comprises plant matter and insects, which they are able to "shoot down". Banded archerfish are also able to capture prey by jumping out of the water and seizing it from low overhanging branches. Young archerfish form small schools while learning aim, increasing the chance that at least one shot will hit the target. Their diet also comprises underwater prey, including crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s and small fishes.
Shooting
Banded archerfish have mouths adapted to spit jets of water over distance, usually to knock prey into the water. The banded archerfish shoots the jet of water by raising its tongue against the roof of its mouth, forming a tube. The opercula then close quickly, pressurizing water along the tube. Most archerfish are able to spit at a range of 150 centimetres (59.1 in), though some larger specimens may be capable of ranges of up to 2 to 3 m (6.6 to 9.8 ). When a prey is shot down, the banded archerfish begins to move towards the place where it will land within 100 millisecondMillisecond
A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....
s and can reach it within 50 ms of its hitting the water.
A study found that banded archerfish could be trained to hit moving targets at an accuracy rate of greater than 50%. According to this study, the ability to hit moving targets is a complex learned behaviour, and can be learnt from other members of the school. The study concluded that fish could shoot more accurately after observing other members of the school shooting.
The banded archerfish is able to hit targets with a high degree of accuracy, despite refraction
Refraction
Refraction is the change in direction of a wave due to a change in its speed. It is essentially a surface phenomenon . The phenomenon is mainly in governance to the law of conservation of energy. The proper explanation would be that due to change of medium, the phase velocity of the wave is changed...
of light in the water. It is believed that they are able to achieve this level of accuracy by positioning their bodies to shoot from directly under the intended target. However, other studies have found that banded archerfish are able to achieve great accuracy even at angles, suggesting that they are somehow able to compensate for refraction. This may also suggest that banded archerfish are capable of three-dimensional tasks.
Breeding
The breeding habits of the banded archerfish are not well known. Banded archerfish first begin to breed when they are about 10 centimetres (3.9 in) long. The banded archerfish reproduces by spawningSpawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
. There are reports that banded archerfish go to saltwater reefs to spawn, but these have not been confirmed. Archerfish lay 20,000 to 150,000 eggs at a time. Banded archerfish rarely breed in captivity.
Distribution and habitat
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
and waters off northern Australia, and less frequently those on the southern coast of Australia. It can be found from India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
eastwards to the Philippine Islands, southwards to Australia, as well as in waters off the Solomon Islands
Solomon Islands
Solomon Islands is a sovereign state in Oceania, east of Papua New Guinea, consisting of nearly one thousand islands. It covers a land mass of . The capital, Honiara, is located on the island of Guadalcanal...
and the Indonesian Archipelago. It has been observed as far east as the New Hebrides (now known as Vanuatu
Vanuatu
Vanuatu , officially the Republic of Vanuatu , is an island nation located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is some east of northern Australia, northeast of New Caledonia, west of Fiji, and southeast of the Solomon Islands, near New Guinea.Vanuatu was...
).
The banded archerfish occurs mainly in areas of brackish water. Mangrove
Mangrove
Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...
estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
are its primary habitat, though it occasionally moves upstream into freshwater rivers. It is associated with reefs and has been reported to occur near overhanging vegetation. While they may move between fresh and salt water
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...
during their life cycle, they do not do so to breed.
Relationship with humans
Banded archerfish are fairly common in the Indo-Pacific and are not currently endangered. They have a minor commercial role in fisheries and may be sold fresh in markets or collected for the aquarium trade. Banded archerfish are threatened by the destructionHabitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
of their mangrove swamp habitat and by pollution.
In aquaria
Species in the genus ToxotesArcherfish
The archerfish are a family of fish known for their habit of preying on land based insects and other small animals by literally shooting them down with water droplets from their specialized mouths...
, including the banded archerfish, are kept as aquarium fish
Aquarium fish
In fishkeeping, species of aquarium fish vary with the water chemistry of the aquarium.For species of fish found in particular types of aquaria, see:*List of brackish aquarium fish species*List of freshwater aquarium amphibian species...
. In aquaria, the banded archerfish can grow up to 25 centimetres (9.8 in) long. They swim at the top level of the aquarium. Banded archerfish can be kept in small groups of three to five; fish of the same size get along but fish that are larger may be aggressive towards those that are smaller, and even try to eat them. They may live from five to eight years in captivity, and occasionally nine or ten. Banded archerfish need warm water, usually between 25 and 30 °C (77 and 86 F). The aquarium should be large with middling amounts of plant growth and plenty of space for swimming. It should be 20 to 30 cm (7.9 to 11.8 ) deep.
Banded archerfish are generally not recommended for average home aquaria
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
despite their attractive appearance because they are difficult to care for and require special conditions. Banded archerfish prefer to shoot and capture live food rather than be fed flake food, making it problematic to feed them. They need brackish water as well as a tall canopy. In the wild they are able to jump out of the water to capture prey on overhanging branches; a tall canopy is required to prevent their jumping out of the aquarium. Banded archerfish should be kept in an aquarium with a volume of at least 45 gal, though a greater volume is preferred. Because of such difficulties in caring for banded archerfish, the species has not yet been successful in captivity.
See also
- Big scale archerfishBig scale archerfishThe big scale archerfish is a species of fish in the Toxotidae family. It is endemic to Australia.-References:* Wager, R. 1996. . Downloaded on 5 August 2007....
(Toxotes oligolepis), also known as the Western archerfish - List of brackish aquarium fish species