Clarias nieuhofii is a species of clariid catfish

Catfish

Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

. It has a wide distribution in Southeast Asia

Southeast Asia

Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...

 including peninsular Malaysia, Java

Java

Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...

, Sumatra

Sumatra

Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

, Borneo

Borneo

Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

 and the Philippines

Philippines

The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

.

This species can be distinguished from other Clarias catfishes, apart from the recently discovered Clarias batu

Clarias batu

Clarias batu is a species of clariid catfish. It is only known from Tioman Island off the eastern coast of Peninsular Malaysia. The eel-like catfish found on this island were originally identified as the widespread species Clarias nieuhofii but comparison of a large series of specimens from Tioman...

and Clarias nigricans

Clarias nigricans

Clarias nigricans is a species of clariid catfish. It is only known from the Mahakam River in eastern Borneo. The eel-like catfish of this region were long assumed to belong to the widespread species Clarias nieuhofii but examination of 6 specimens purchased from a fish market in Samarinda in 1999...

, by the greatly elongated body which gives it a remarkably eel

Eel

Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...

-like appearance. The colour is generally grey with two rows of white spots running along the length of the body just below 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...

 and 13 or 14 vertical rows of white spots just above the line. Specimens of up to 40 cm standard length

Fish measurement

Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...

have been recorded.