''Hyporhamphus affinis'', the tropical halfbeak, tropical garfish, insular halfbeak or coral reef halfbeak, is a species of schooling marine fish from the family

Hemiramphidae Hemiramphidae is a family of fishes that are commonly called halfbeaks, spipe fish or spipefish. They are a geographically widespread and numerically abundant family of epipelagic fish inhabiting warm waters around the world. The halfbeaks are ...

. It is distributed through the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

regions and has been recorded in the Mediterranean Sea which it reached through the

Suez Canal The Suez Canal ( arz, قَنَاةُ ٱلسُّوَيْسِ, ') is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea to the Red Sea through the Isthmus of Suez and dividing Africa and Asia. The long canal is a popular ...

Description

''Hyporhamphus affinis'' has a blue back with a silvery stripe on side, silvery white underparts and a blue

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

while the other fins are colourless. They grow to a maximum length of 38 cm. The distal half of the underside of the elongated lower jaw is bright red. There is a well developed anterior lobe on the

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 conv ...

and the caudal fin has a slightly longer lower lobe than the upper. The upper jaw is scaled, the pre-orbital region is much longer than the upper jaw.

Distribution

''Hyporhamphus affinis'' has an Indo-Pacific distribution from the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

and coasts of eastern Africa east through the Indian Ocean islands to

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

, and islands of

Oceania Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern Hemisphere, Eastern and Western Hemisphere, Western hemispheres, Oceania is estimated to have a land area of ...

, although it is absent from

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

and the Indo-Malayan Archipelago. It has been first recorded in the

Levantine Sea The Levantine Sea (Arabic: بحر الشام, tr, Levanten Denizi, el, Θάλασσα του Λεβάντε) is the easternmost part of the Mediterranean Sea. Geography The Levantine Sea is bordered by Turkey in the north and north-east co ...

in 1964 and has since spread as far west as

Libya Libya (; ar, ليبيا, Lībiyā), officially the State of Libya ( ar, دولة ليبيا, Dawlat Lībiyā), is a country in the Maghreb region in North Africa. It is bordered by the Mediterranean Sea to the north, Egypt to Egypt–Libya bo ...

.Atlas of Exotic Fishes in the Mediterranean Sea (Hyporhamphus affinis). 2nd Edition. 2021. 366p. CIESM Publishers, Paris, Monaco.https://ciesm.org/atlas/fishes_2nd_edition/Hyporhamphus_affinis.pdf

Biology

''Hyporhamphus affinis'' is found mainly at depths between 0 and 6m in proximity to coral reefs and islands but extends a little further from shore than '' Hyporhamphus dussumieri'' with which it is largely

sympatric In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sh ...

. It occurs in schools and feeds mainly on

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 ...

, as well as small fish and detritus. The eggs are covered with adhesive filaments and are attached to floating and benthic objects.

References

{{Taxonbar, from=Q2132931 affinis Fish described in 1866 Taxa named by Albert Günther