The smallscale archerfish (''Toxotes microlepis'') is a

perciform Perciformes (), also called the Percomorpha or Acanthopteri, is an order or superorder of ray-finned fish. If considered a single order, they are the most numerous order of vertebrates, containing about 41% of all bony fish. Perciformes means " ...

fish of genus ''Toxotes''. As its name suggests, the scales of the smallscale archerfish are smaller than those of other archerfish. They reach a maximum length of . Smallscale archerfish live in the tropical Indo-Pacific region and are

potamodromous Fish migration is mass relocation by fish from one area or body of water to another. 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 thousan ...

, moving between fresh and brackish water through their lifetimes.

Description

Smallscale archerfish have a pointed snout and large eyes. The back is flat and the belly is curved. There is only one

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

, with four to five

dorsal spine Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsa ...

s. The fourth spine is longer than the third. The second dorsal spine is slightly shorter than the third anal spine, which itself is shorter than the

soft ray Fish anatomy is the study of the form or morphology of fish. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish. In practice, fish anatomy and fish physiolo ...

s. There are usually 40 to 42 lateral line scales, though some specimens found in the Mekong had 34 to 37. The species '' T. blythii'' was formerly thought to be identical to ''T. microlepis''. Differences in structure and colouration caused the splitting of ''T. blythii'' into a new species. Like other archerfish, they have dark, wedge-shaped bands or spots on its flanks, which can be yellow to silvery. They reach a maximum length of in the wild, and in captivity. The smallscale archerfish is sometimes confused with the banded archerfish, ''T. jaculatrix''. Both species have four or five wedge-shaped bars on their flanks. However, the bars of banded archerfish extend to the

whilst those of the smallscale archerfish do not; they stop below the dorsal fin, with another dark spot on the fin itself. The smallscale is also has a shorter snout than other archerfish.

Diet

Smallscale archerfish eat terrestrial insects (which they can shoot down),

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

, crustaceans, and insect larvae.

Distribution and habitat

Smallscale archerfish inhabit large rivers and

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environme ...

in Asia and the Indo-Pacific. They are distributed throughout the

Mekong The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's twelfth longest river and the third longest in Asia. Its estimated length is , and it drains an area of , discharging of water annuall ...

and

Chao Phraya The Chao Phraya ( or ; th, แม่น้ำเจ้าพระยา, , or ) is the major river in Thailand, with its low alluvial plain forming the centre of the country. It flows through Bangkok and then into the Gulf of Thailand. Et ...

river basins as well as waters off the

Malay Peninsula The Malay Peninsula ( Malay: ''Semenanjung Tanah Melayu'') is a peninsula in Mainland Southeast Asia. The landmass runs approximately north–south, and at its terminus, it is the southernmost point of the Asian continental mainland. The are ...

, Sumatra and

Borneo Borneo (; id, Kalimantan) is the List of islands by area, third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java Isl ...

. They can be found near the shores of moving and standing waters, usually with overhanging plants. The smallscale archerfish is described as a "freshwater archerfish", as it does not move into saltwater during its life as do some other archerfish. It is found upstream from the estuary more often than other species of the genus.

Taxonomy

The populations of archerfish assigned to the smallscale archerfish that occur in the rivers of southeast Asia were found to be three different species by work published in 2018, this has not yet been reflected in

Fishbase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

. The new species are ''

Toxotes mekongensis Toxotes may refer to: Biology * Banded archerfish (''Toxotes jaculatrix''), Pallas 1767 * ''Toxotes chatareus'', Hamilton 1822 * Smallscale archerfish (''Toxotes microlepis''), Günther 1860 * Big scale archerfish (''Toxotes oligolepis''), Bleeker ...

'' from the Mekong, '' Toxotes siamensis'' from the Chao Phraya and '' Toxotes sundaicus'' from

, Sumatra and possibly the

. This same study found that ''Toxotes microlepis'' is a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are al ...

of '' Toxotes blythii''. Abstract

Relationship to humans

Some aquarists believe the smallscale archerfish is the most frequently traded

archerfish The archerfish (spinner fish or archer fish) form a monotypic family, Toxotidae, of fish known for their habit of preying on land-based insects and other small animals by shooting them down with water droplets from their specialized mouths. The ...

. It is often confused with other archerfish (such as the banded archerfish and

largescale archerfish ''Toxotes chatareus'', sometimes known by the common names common archerfish, seven-spot archerfish or largescale archerfish, is a species of perciform fish in the archerfish genus '' Toxotes''.Martin F. Gomon & Dianne J. Bray (2011Sevenspot Ar ...

), and may be sold with the others as one species. Smallscale archerfish do not need brackish water as do other members of its genus (though it can also live in brackish water); it is thus sometimes sold as the "freshwater archerfish". In Thailand smallscale archerfish is called ''Pla Suea Pon Nam Nakhon Sawan'' ( th, ปลาเสือพ่นน้ำนครสวรรค์; lit: Nakhon Sawan archerfish) or ''Pla Suea Pon Nam Leung'' (ปลาเสือพ่นน้ำเหลือง; yellow archerfish) because it is wild caught from Bueng Boraphet, Nakhon Sawan Province, and because it has a bright yellow colour. It is often the most common species in aquarium shop.

References

* {{Taxonbar, from=Q4925742 Archerfish Fish described in 1860 Taxa named by Albert Günther Fish of the Mekong Basin Fauna of Brunei Fish of Cambodia Freshwater fish of Indonesia Fish of Laos Freshwater fish of Malaysia Fish of Thailand Fish of Vietnam Freshwater fish of Borneo