''Clarias batu'' (sometimes known under the common name Tioman walking catfish) is a species of clariid

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) 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 three largest species alive, ...

. It is only known from

Tioman Island Tioman Island ( ms, Pulau Tioman) is a mukim and an island in Rompin District, Pahang, Malaysia. It is located off the east coast of the state, and is some long and wide. It has seven villages, the largest and most populous being Kampung Te ...

off the eastern coast of

Peninsular Malaysia Peninsular Malaysia ( ms, Semenanjung Malaysia; Jawi: سمننجڠ مليسيا), or the States of Malaya ( ms, Negeri-negeri Tanah Melayu; Jawi: نڬري-نڬري تانه ملايو), also known as West Malaysia or the Malaysian Peninsula, ...

. The

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

-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 with a series of ''C. nieuhofii'' from the mainland revealed consistent and distinctive differences indicating a separate species. This is an elongated catfish up to 30.5 cm (12.0 inches)

standard 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 ...

. It can most readily be distinguished from ''C. nieuhofii'' by the fact that the

dorsal 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 * Dorsal co ...

and

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 ...

s are clearly separated from 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 ...

whereas ''C. nieuhofii'' has all these fins confluent. Care should be taken however as specimens of ''C. batu'' have been recorded which have apparently confluent fins as a result of healing after suffering damage.

References

Clarias Freshwater fish of Malaysia Endemic fauna of Malaysia Taxa named by Kelvin Kok Peng Lim Taxa named by Heok Hee Ng Fish described in 1999 {{catfish-stub