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he month of June 2024 brings us to the Akysidae family and a small catfish with a very long scientific name. The genus name Pseudobagarius means that it is tautonymous with Akysis pseudobagarius, proposed for members of the “pseudobagarius group” of Akysis; pseudo-, false, referring to striking (but phylogenetically false) resemblance to the sisorid genus Bagarius. The specific name leucorhynchus: leuco-, white; rhynchus, snout, referring to the white end of the muzzle.

Pseudobagarius leucorhynchus is a small catfish found in the Mekong river in Thailand. Specimens as small as 3.0cm (1¼ins) have been found to be sexually mature and carrying nearly ripe eggs. This genus corresponds to the “pseudobagarius group” of species of the genus Akysis that was first recognised by Ng & Kottelat (1998). A look-a-Like, Akysis pulvinatus, is thought to mimic this catfish in the same habitat, so called a Müllerian mimic.

 Pseudobagarius leucorhynchus

Henry Weed Fowler (March 23, 1878 – June 21, 1965) was an American zoologist born in Holmesburg, Pennsylvania. He studied at Stanford University under David Starr Jordan. He joined the Academy of Natural Sciences in Philadelphia and worked as an assistant from 1903 to 1922, associate curator of vertebrates from 1922 to 1934, curator of fish and reptiles from 1934 to 1940 and curator of fish from 1940 to 1965. He published material on numerous topics including crustaceans, birds, reptiles and amphibians, but his most important work was on fish. In 1927 he co-founded the American Society of Ichthyologists and Herpetologists and acted as treasurer until the end of 1927

None

Akysis leucorhynchus

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Asia: Thailand; Choa Phraya basin and southern Peninsular. Phitsanulork Province. Type locality: Chieng Mai, North Siam.

3.0cm (1¼ins)

18-24°C (63-75°F)

Pseudobagarius leucorhynchus is slender and has a rather stout dorsal spine, a distinct adipose fin, and longish, broad-based barbels. Akysidae with the following combination of characters: snout extending well anterior of margin of lower jaw, rendering mouth subterminal; narial openings relatively large and closely set; and caudal fin deeply forked. Dorsal soft rays (total): 6 - 6; Anal soft rays: 6 – 8; Vertebrae: 31 – 34. Distinguished from all its congeners by the following combination of characters: light-yellow snout with a sharp, contrasted edge discrete line demarcation; presence of 4-6 small serrae on the posterior edge of pectoral spine; head width 20.3-25.5% SL; depth of caudal peduncle 5.5-7.1% SL;  length of anal-fin base 9.7-16.6% SL;  length of nasal barbel 16-38% HL; 5 branchiostegal rays; and caudal fin deeply emarginate.

Much like the Akysis genus. They are easy to keep for any decent fishkeeper. You can keep in small tanks (30cm wide x 20cm high x 30cm deep) with a sand bottom, small pipes, and caves. They will either bury themselves in the sand or hide in caves and pipes. They are not usually active during the day but will spring to action and eat voraciously and crazily if food is put in the tank.

Not recorded but specimens as small as 3.0cm (1¼ins) have been found to be sexually mature and carrying nearly ripe eggs.

Not recorded

They will eat bloodworm, chopped earthworms, whiteworm, daphnia, and sinking pellets (although they seem to prefer live or frozen food).

Adipose fin: Fleshy finlike projection without rays, behind the rayed dorsal fin.
Anal fin: The median, unpaired, ventrally located fin that lies behind the anus, usually on the posterior half of the fish.
Barbels: Whisker-like structure on the heads of most catfish.
Branchiostegal: Slender bones which support the gill membranes.
Caudal fin: The tail.
Caudal peduncle: The narrow part of a fish's body to which the caudal or tail fin is attached.
Dorsal fin: The primary rayed fin(s) on top of the body.
Emarginate: Concave; used to describe the posterior border of a caudal fin which is inwardly curved; a caudal fin with a slightly concave margin.
Nasal barbel: On top of the head, by the nostrils. (nasal barbels).
Pectoral: The paired fins just behind the head.
Serrae: Saw-like notches along an edge.

Pseudobagarius: Tautonymous with Akysis pseudobagarius, proposed for members of the “pseudobagarius group” of Akysis; pseudo-, false, referring to striking (but phylogenetically false) resemblance to the sisorid genus Bagarius.
leucorhynchus: leuco-, white; rhynchus, snout, referring to the white end of the muzzle.

Photo Credits

© Nonn Panitvong
Map: Kmusser - File:Chaophrayarivermap.png using Digital Chart of the World and GTOPO data.