Nilwala

The Ceylonese combtail, Belontia signata, is a labyrinth fish endemic to the central and southern river systems of Sri Lanka. Also referred to as the 'Ceylon fighting fish', it differs from B. hasselti in its reddish body and the absence of mosaic patterning in the unpaired fins. At least three putative phenotypes have been recorded, one described as the questionably valid subspecies B. s. jonklaasi. It is not recommended for the average community aquarium.

The barred 'danio', Devario pathirana, is a devario known only from a few small streams in the Nilwala River watershed of southwestern Sri Lanka. It has 7 to 11 dark blue, irregular vertical bars on the front of each flank and a short horizontal stripe on the caudal peduncle. Although endangered in nature, it is bred commercially in limited numbers and is sometimes sold as the 'tiger' or 'Ceylon' danio.

Lepidocephalichthys jonklaasi is a cobitid loach endemic to the 'wet zone' of south-western Sri Lanka, known from at least five localities. Records exist from the Gin, Kalu, Nilwala and Bentota river basins plus a small blackwater creek near the Kottawa Forest Reserve. Its conservation status perhaps precludes its suitability for the hobby. Broad dark bars on the caudal fin and large, vertically elongated black spots on the flanks identify it.

The ornate paradisefish, Malpulutta kretseri, is a labyrinth fish from the 'wet zone' of southwestern Sri Lanka. It has been recorded from the Gin, Kelani, Kalu, Nilwala and Bentota river basins. The only member of its genus, it is protected by law in Sri Lanka although it still appears in the aquarium trade from time to time. Three colour forms exist, differing in the amount of reddish, violet or bluish pigmentation in the fins.

The black ruby barb, Pethia nigrofasciata, is a small cyprinid endemic to the Kelani and Nilwala river basins in the 'wet zone' of Sri Lanka. Sometimes traded as 'purple-headed barb' or 'ruby barb', it has three dark, vertical flank markings, and in spawning males the head and front of the body turn reddish-purple. Farm-raised fish are fairly adaptable in water chemistry, while wild stock are likely to prefer slightly acidic to neutral conditions.

The two-spotted barb, Puntius bimaculatus, is a small cyprinid from Sri Lanka and southern India. It lives in flowing hill streams and quieter stretches in the middle reaches of rivers, but tends to be absent from lowland environments. Also called the 'redside barb', it has 7 branched dorsal-fin rays and round dark spots at the base of the dorsal and caudal fins. Generally very peaceful, it is a schooling species and at least 6-10 should be kept.

The cherry barb, Puntius titteya, is a small cyprinid endemic to the Kelani and Nilwala river basins in the southwestern 'wet zone' of Sri Lanka. Among the most ubiquitous small cyprinids in the hobby and an unreserved choice for beginners, it is sold mostly as commercially farmed stock, including albino and 'super red' strains. Generally very peaceful, it is a schooling species and at least 6-10 should be kept.

The fire rasbora, Rasboroides vaterifloris, is a small cyprinid endemic to the Kalu, Bentota, Gin and Nilwala river basins of southwestern Sri Lanka. Colour varies with locality, and red, orange and yellow-finned forms are known. Its delicate nature causes problems in shipping, and reports suggest the more highly coloured fish are becoming scarcer in the wild, possibly because selective collection for the trade has altered the structure of wild populations.

The green chromide, Etroplus suratensis, is a euryhaline cichlid from peninsular India and Sri Lanka, growing to 350 mm SL. It mostly inhabits brackish estuaries, coastal lagoons and lower river reaches. Not especially popular in the hobby, it is an important food fish, and some populations have crashed through over-exploitation. In Sri Lanka's Negombo Lagoon Pseudetroplus maculatus has been seen acting as its cleaner while also eating its eggs and fry.