''Polynemus multifilis'', the elegant paradise fish is a species of

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

, a threadfin from the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Polynemidae Threadfins are silvery grey perciform fish of the family Polynemidae. Found in tropical to subtropical waters throughout the world, the threadfin family contains eight genera and about 40 species. An unrelated species sometimes known by the n ...

which is found in rivers in

southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

Description

''Polynemus multifilis'' is a medium-sized species of threadfin which attains a maximum standard length of . It has a pointed snout and the dorsal profile of the head is almost straight, There are two separate

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 ...

s, the first dorsal fin contains 8 spines which are all of a similar thickness at their bases and the second dorsal fin has a single spine and 14-16 soft rats. The

anal 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 s ...

contains 3 spines and 11 to 13 soft rays and its base is shorter than that of the second dorsal fin. The

pectoral 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 ...

has 14-16 unbranched soft rays and its tip reaches the origin of the anal fin. There are normally fourteen, rarely thirteen or fifteen, pectoral filaments on each side of the body and the count on each side is not necessarily symmetrical. The longest of these are longer than the

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of the fish. The lateral line contains 83-99 pored scales and is simple, it starts at the upper margin of the gill slit and extends to the middle of the

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 s ...

. The caudal fin is deeply forked but neither lobe bears any filaments. The upper head and upper body are dark purplish-blue and below this the fish is silver in colour. The bases of the dorsal, anal and caudal fins are greyish white while the forward margin of the pelvic fin white. The remaining parts of these fins are semi-transparent as is the pectoral fin.The pectoral filaments are white.

Distribution

''Polynemus multifilis'' has been recorded from the Chao Phraya River system in Thailand, the Musi and Batanghari rivers in southeastern Sumatra, Indonesia, and on

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 ...

in the Sampit and Barito rivers in southern

Kalimantan Kalimantan () is the Indonesian portion of the island of Borneo. It constitutes 73% of the island's area. The non-Indonesian parts of Borneo are Brunei and East Malaysia. In Indonesia, "Kalimantan" refers to the whole island of Borneo. In 2019, ...

, Indonesia. This species is absent from the Kapuas River where the endemic '' Polynemus kapuasensis'' appears to replace it.

Habitat and biology

''Polynemus multifilis'' is found in freshwater rivers where there is a sandy or muddy substrate. It is a carnivorous species which preys on crustaceans, small fishes and benthic invertebrates.

Fisheries

''Polynemus multifilis'' is highly regarded as a food fish, especially in Thailand. It is also caught for export to Japan as an ornamental fish.

Species description

''Polynemus multifilis'' was first formally described in 1843 by Coenraad Jacob Temminck and Hermann Schlegel with the

type locality Type locality may refer to: * Type locality (biology) * Type locality (geology) See also * Local (disambiguation) * Locality (disambiguation) {{disambiguation ...

being given as near Banjarmasin on Borneo.

References

{{Taxonbar, from=Q958308 multifilis Taxa named by Coenraad Jacob Temminck - 1846 Taxa named by Hermann Schlegel Fish described in 1843 Fish of Indonesia Fish of Thailand