Songkhram

This species is included in the Betta splendens complex of closely-related species within the genus, of which members share the following set of characters: head length short 22-31 % SL; often a brightly-coloured body; iris of the eye with iridescent green or blue patches; body elongate or slender; opercles parallel when head viewed dorsally; caudal-fin rays red or brown and contrasting with the iridescent interradial membranes; unpaired fins without an iridescent margin; opercle with red or blue vertical bars in males; dorsal-fin rays 0-II, 7-9; anal-fin rays II-V, 21-26.

An exclusive inhabitant of fresh, normally standing, waters including shallow pools, ditches, rice paddies and clear water swamps. The type locality is a small ditch measuring just 3 - 6 metres in width and 0.5 - 2 metres deep. The water was clear and the substrate composed of sand, detritus and mud with growths of the macrophytes Nymphaea lotus, Jussiaea repens and Hydrilla verticillata.

It can be distinguished from congeners by its small adult size and presence of a single solid dark midlateral stripe on the body, above which is a series of dark blotches forming a second stripe. In the similar but larger, T. schalleri the upper stripe is more variable depending on the mood of the fish, sometimes fading entirely.

This species is one of the more commonly-encountered botiids in the hobby and is also sold as 'blue', 'orange-finned', or 'red-finned' botia/loach. It's sometimes subject to artificial colouring with bright blue or purple dyes and we strongly recommend you do not purchase such fish (they're illegal in several countries).

This species is also referred to as 'royal knifefish' in the aquarium trade but arguably has no place in the ornamental hobby given its adult size and specialised requirements. It can be distinguished from congeners by presence of many small, dark spots on the anterior portion of the body which merge to form oblique, irregular stripes extending onto the anal and caudal fins posteriorly.

This species can be distinguished from congeners by the following combination of characters: body depth fits 2.5-2.7 times in SL; 28-31 +2-3 lateral line scales; 14-16 circumpeduncular scale rows; 5-5½ scale rows between the lateral line and dorsal-fin origin; a triangular distal blotch on the dorsal-fin; a few body scales with crescent-shaped black edges; a thin dark margin on the dorsal-fin, posterior to the distal blotch; a dark posterior margin on the caudal-fin; normally a single pair of rudimentary barbels present.

Known from the middle Mekong basin in Laos and Thailand, and may be endemic to the Khorat Plateau. Records exist from the Mun and Songkhram watersheds in northeastern Thailand, and a number of Mekong tributaries in laos, including the Nam Mang and Nam Kou drainages. Type locality is 'Nam Mang downstream of Ban Thabok, between 18°22'25"N, 103°13'30"E, and about 1 kilometer upstream, Vientiane Province, Laos'.