field guide to the freshwater fishes of singapore

Index of fishes
General parts of a fish
Kelvin K P Lim and Peter K L Ng
  Family Clariidae
Africa Middle East, Asia. These catfishes are rather elongated with a flattened, broad, bony head, and wide mouth. They possess four pairs of long, rather stiff barbels. They are mainly nocturnal in habit, possessing accessory respiratory organs above their gills (like the labyrinth fishes) to enable them to utilise atmospheric oxygen.

Genus Clarias
Primarily freshwater fish; oviparous; omnivorous (though large individuals are predatory on small fishes); solitary; benthic. Clarias has the anal and dorsal fins long and without spines. The pectoral fins however, have a strong spine (said to contain venom) which can inflict a nasty wound if the fishes are mishandled.
The two species in Singapore possess an accessory respiratory organ in the form of an arborescent organ at the hind part of their gill cavity. They sometimes travel out of water over land. This they do by wriggling their body to propel themselves forward, using their strong pectoral spines to push on, and breathing via their skin and arborescent organs. As a result, they are commonly called "walking catfishes".
close-up photo of organ
Arborescent organ of
Clarias batrachus

close-up of head showing barbels
Common Walking Catfish
Clarias batrachus
Ikan Keli Kayu, name in chinese characters

Primarily freshwater fish; 55 cm. Indigenous, widespread and common. Forested, rural or disturbed streams, canals, drains, ponds, reservoirs and swamps. Tolerates slightly brackish water.
This is the commonest freshwater catfish in Singapore. It is dark-grey or brown, often with a series of pale spots on the sides. Although cultivated in ponds in Thailand and elsewhere for food, it is less frequently eaten by Singaporeans. Albino (with pink eyes) and bicolour ("Piebald") strains are often seen in the aquaria.

It can be distinguished from the Forest Walking Catfish by the shorter distance between the bony end of the skull and the first ray of the dorsal fin and the colour is generally duller.
close-up photo of head and dorsal fin
Clarias batrachus (dorsal view)

close-up photo of head and dorsal fin
Clarias teijsmanni (dorsal view)

photo of whole fish, side viewForest Walking Catfish
Clarias teijsmanni
Ikan Keli Hutan, name in chinese characters

20 cm. Indigenous, endangered (?), Forest streams.

Unlike the more adaptable C. batrachus, this catfish is more or less confined to the forest. It is very similar to the Common Walking Catfish, and it is not easy to tell these two species apart in the field (see above). Clarias teijsmanni has a more squarish head, and also tends to be darker in colour, the sides often adorned with rows of white spots which tend to be more distinctive than those of C. batrachus.
Freshwater habitats
Fishes in Singapore
Amazing Fishy Facts
About the guidebook
From A Guide to Common Freshwater Fishes of Singapore by Kelvin K P Lim and Peter K L Ng
Published by the Singapore Science Centre and sponsored by BP

@Raffles Museum of Biodiversity Research and Singapore Science Centre