Order Cypriniformes ( Cypriniformes )
Family Cyprinidae ( Cyprinidae )
Genus Crossocheilus — Crossocheilus.
— Short-nosed flying fox, oblongus — Crossocheilus oblongus [Kuhl & Van Hasselt, 1823]. Synonym: Labeo oblongus, Epalzeorhynchos stigmaeus. (Eng. Short Nosed Flying Fox). Southeast Asia, mainly in Thailand and Indonesia. Maximum length up to 10 cm. It has two pairs of tiny barbels on the lower jaw. This is a close relative of the Siamese algae eater, and it is quite possible that specimens of this fish were found both in its shipments and during the export of false “Siamese” algae eaters.
In appearance, this is still the same Siamese flying fox. The only difference, in fact, is only in the ultimate sizes of the adult fish. The oblongus reaches a smaller length than the Siamese one. Body shape and color are basically the same as those of the Siamese algae eater and “false Siamese algae eaters”. All fins are transparent and the black horizontal stripe does not extend to the caudal fin. The stripe has smooth edges rather than reticulated ones as in the Siamese algae eater.
In 2009, Tan and Kottelat described a new laterally-striped subspecies, Crossocheilus obscurus, from the Hari Batang River in Sumatra. This species grows relatively larger, up to 14 cm. It has one pair of barbels, the black lateral stripe does not contrast sharply at the edges, is slightly curved downwards, and continues on the lateral rays of the caudal fin. It loves to eat algae when very young, but soon prefers dry food, flakes, bloodworms, etc. However, this fish will not solve the algae problem. Generally a peaceful fish that is best kept in pairs.
— Crossocheilus langei — Crossocheilus langei [Bleeker, 1860]. Synonym: Crossochilus langii. (Eng. Red Algae Eater). Indonesia, Malaysia, Sumatra. Can grow up to 14 centimeters. Body and fins brownish. A golden sheen is sometimes visible on the head. A wide blackish-brown lateral stripe starts from the tip of the snout, runs through the entire body, and ends at the end of the caudal fin. The stripe strictly occupies three rows of scales and is completely straight. When excited or during a fight, the stripe takes on a paler brown color, but does not change its width. The almost straight lateral line is located in the center of the stripe.
The dorsal region is olive-brown, the belly is white with an elongated blackish spot on the lower part, approximately midway between the ends of the ventral and anal fins. This spot is characteristic of Crossocheilus langei. The back has a faint golden sheen and sometimes a golden shiny spot on the head as well. Dorsal fin without stripes or spots. The eye is reddish, its lower third is whitish. There are two fleshy rostral barbels and filamentous maxillary barbels. In some specimens, the maxillary barbels are barely visible — they can be seen using a magnifying glass.
They are active and fast swimmers, thrive when kept in groups, but are aggressive towards their own species and other algae eaters. However, they are less aggressive than similar fish such as Gyrinocheilus aymonieri and Epalzeorhynchos bicolor. They can jump out of the aquarium through any crack at any moment, so a cover glass is necessary. An excellent algae eater, including red algae, especially at a young age. Plant foods should make up the bulk of its diet; protein foods lead to health problems. With proper care, they can live up to 10 years. Water temperature 24-26°C, pH 6.0-7.5, and water hardness 5-20° dH.
Identification: Genus Crossocheilus — Crossocheilus langei, oblongus.
— Gangetic latia — Crossocheilus latius [Hamilton, 1822]. Synonym: Crossocheilus gohama, sada. India, Bangladesh, Myanmar, China, mountain streams and rivers with high water flow, light, and oxygen content, stays on stones covered with algae. 12 cm. They differ from others by the absence of a lateral stripe. The main color is grayish-bluish or greenish-brownish with irregular spots. Fins are pinkish-gray, usually without spots. Sometimes there is an indistinct wide stripe along the midline.
Intolerant of the accumulation of organic waste and require clean water, high dissolved oxygen levels, and good water movement. Deals wonderfully with all kinds of algae. Eats algae of all kinds, fouling on stones and decorations, flakes, spirulina tablets, vegetables. High-protein products should be avoided as the fish is unable to efficiently digest certain components, and long-term consumption can lead to excessive fat deposition and loss of reproduction capacity. T 20-25°C; dH 5-15°; pH 6.5-7.5.
— Reticulated flying fox — Crossocheilus reticulatus [Fowler, 1934]. Synonym: Epalzeorhynchos coatesi, Crossocheilus tchangi. (Eng. Reticulated Flying Fox, Silver Flying Fox). Thailand, Mekong and Chao Phraya river basins. 16 cm. Silvery-olive with a greenish tint, with reticulated scales and black speckles on the body. Eyes are reddish, a black spot at the base of the tail. All fins are semi-transparent with yellow tints. Sexual dimorphism is not clearly expressed, but it has been noted that females are larger and fuller than males.
Quite peaceful as long as they are kept in small groups. They prefer strong currents, driftwood with rounded edges, smooth stones, and broad-leaved plants. They like to stay near the bottom or on wide leaves of plants the most. They eat leftover food. They clean aquarium glass from algae. Plant food forms the basis of feeding. If there is not enough algae, the diet should be supplemented with blanched vegetables. dH 5-15°; pH 6.5-7.5; T 20-25°C.
Danio albolineatus, aesculapii, choprae.
Crossocheilus atrilimes, citripinnis, siamensis. 
