Sai Buri

Boraras urophthalmoides is a miniature cyprinid from southern and central Thailand, Cambodia and Vietnam, including the moats of Angkor Wat. It inhabits shallow, clear, vegetated swamps, marshes, floodplains and rice paddies. Some populations develop an orange-red stripe that leads to confusion with B. brigittae, but B. urophthalmoides is smaller, with a distinct round, dark blotch on the caudal peduncle and a long, unbroken lateral stripe. It is sometimes sold as the 'exclamation-point rasbora'.

Homaloptera parclitella is a 'lizard' loach from Peninsular Malaysia and the Sai Buri, Bang Nara and Kolok river systems of southern Thailand. It was previously considered a form of H. orthogoniata and may be seen identified as such online and in print. It always has two large, saddle-shaped markings on the back, where H. orthogoniata has three, and it lives in swift, clear, oxygen-saturated streams.

Sold as 'blue hillstream trout', Opsarius bernatziki is a cyprinid from peninsular Thailand and Tanintharyi, Myanmar, south of the Isthmus of Kra. It inhabits well-oxygenated, moderate to fast-flowing rivers and streams, usually 10-20 km or more from the sea. Six or seven bluish vertical bars on each flank and a large blotch at the caudal-fin base help identify it. Like its congeners it is too fast and vigorous a feeder for the general community.

Puntigrus partipentazona is a small cyprinid recorded from numerous river basins in Vietnam, Cambodia, Laos, Thailand and Peninsular Malaysia. It is easily told from congeners because the dark blotch on its dorsal fin extends onto the body. Typically found in heavily vegetated parts of rivers and sluggish streams, it is generally peaceful, though rival males continually battle for position within the group.

The fork-tailed loach, Vaillantella maassi, is a loach from Sumatra, Borneo, Peninsular Malaysia and southern Thailand. Traded as 'chocolate scissor-tailed loach' and 'dragon loach' among other names, it has a bluish-brown body with an orange to yellow dorsal stripe. Rarely traded in numbers, it is among the more reclusive loaches and can be aggressive with its own kind and other fishes.