Danio

The panther danio, Danio aesculapii, is a small cyprinid endemic to the Rakhine Yoma (Arakan mountains) of western Myanmar. It continues to be traded under names such as 'Danio sp. pantheri', 'D. sp. hieroglyph' and 'D. sp. TW03'. Six or seven brown vertical bars on the front of the body and two rows of small brown spots behind them set it apart from congeners. One of the smaller members of the genus at 25 to 30 mm, it inhabits seasonal streams and pools.

The pearl danio, Danio albolineatus, is a small cyprinid recorded from Myanmar and Indochina south to Peninsular Malaysia and Sumatra. Colour and patterning differ between localities, and doubts remain whether it is a single species or a group of closely related fish. Wild examples are rare in the trade, with most produced commercially in South East Asia or eastern Europe, and some of the fish traded are likely to be hybrids with D. roseus.

The glowlight danio, Danio choprae, is a small cyprinid from northern Myanmar, apparently restricted to the Mogaung Chaung system. Available in the trade since around 2003, it quickly became one of the most popular small danionins in the hobby, and commercial breeding means wild fish are hard to come by. It closely resembles D. flagrans, and the spelling 'choprai' seen in some sources is not the accepted one.

The moustached danio, Danio dangila, is a cyprinid from the Ganges and Brahmaputra drainages, with most records from Nepal, India and Bangladesh. The common name refers to its exceptionally long barbels, and despite its apparent abundance in nature it remains uncommon in the hobby. Its constant activity can upset slow-moving or timid tankmates, so it suits larger tanks with similarly-sized fishes, and adult size appears to vary by population from 60 to 130 mm.

Danio erythromicron is a miniature danionin from Lake Inle and its surrounding watershed in Shan State, eastern Myanmar. Fully grown at just 20 mm, it is sold under trade names including 'emerald dwarf danio' and 'cross-banded dwarf rasbora'. It will not do well in acidic water, and there is limited evidence that it has been hybridised with D. margaritatus and the offspring sold as females of that species.

The Yoma danio, Danio feegradei, is a cyprinid considered endemic to the western slopes of the Rakhine Yoma in western Myanmar. Seen in the hobby since around 2005, it is traded under names such as 'Danio sp. Yoma', 'D. sp. gold laser' and 'D. sp. rocket'. The spot-like markings on the flanks vary, and some specimens lack them entirely. It inhabits small, seasonal forest streams, and its constant activity suits it to larger tanks with similarly sized fishes.

The northern glowlight danio, Danio flagrans, is a small cyprinid known only from a handful of streams near Putao in far northern Myanmar. It has reached the hobby in limited numbers, also traded as 'Danio sp. Putao', 'D. putaoensis' or 'D. cf. choprae'. It looks very similar to D. choprae and is told apart by its more slender body, longer barbels and an almost always present lateral line.

Danio jaintianensis is a small cyprinid known only from the Jaintia Hills of Meghalaya, in the Brahmaputra system of northeastern India. It is likely to be restricted to small, slower-moving hill streams with gravel and rocky substrates and thick marginal vegetation. It is best kept in an unheated tank and tends to struggle above 25 °C for long periods. Its temperature needs and rarity make it hard to recommend for the general community.

The blue danio, Danio kerri, is a small cyprinid from islands and the adjacent mainland of south-western Thailand. It was described from Phang Nga province and has since been recorded from Phuket, Ko Lanta, Langkawi, Krabi and Ranong. Base body colour is powdery-blue in the north of its range and more yellowish in the south, with pinkish-yellow lateral stripes. It inhabits clear forest streams over rocks and gravel, and can be hard to find in aquarium shops.

The orange-finned danio, Danio kyathit, is a small cyprinid from the upper Irrawaddy (Ayeyarwady) River drainage in northern Myanmar. Its body patterning varies, with the lateral stripes solid in some specimens and wavy or broken into spots in others, and the striped form was recovered as genetically distinct from the spotted one. Striped fish resemble D. rerio but have much longer barbels and red to orange fins. Very peaceful, it seems most comfortable at 16 to 26 °C.

The celestial pearl danio, Danio margaritatus, is a miniature cyprinid from the Salween drainage in Shan State, eastern Myanmar. First marketed as 'Galaxy Rasbora' after its discovery in 2006, it became one of the most hyped fishes the hobby has known, and Myanmar banned exports in 2007 after reports of overfishing. Intensive commercial breeding means specimens with spotted fins or deformities are now common in the ornamental trade.

Much of Meghalaya consists of forested hills which receive a great deal of rainfall and many of its waters flow swiftly. This species typically inhabits high elevation (> 1000 m amsl) streams running over rocky, boulder-strewn substrates with few aquatic plants, although at some localities the flow may be more sluggish with riparian vegetation providing shade.

The dwarf spotted danio, Danio nigrofasciatus, is a small cyprinid endemic to central Myanmar, on both sides of the Bago Yoma range. It inhabits streams, minor rivers, ponds, ditches and rice paddies, many of them seasonal. A spotted anal-fin separates it most easily from similar species such as D. rerio and D. kyathit. Very peaceful but rather timid, it does best alone or with similarly sized species that enjoy similar conditions.

The zebra danio, Danio rerio, is a small cyprinid from India and Bangladesh, found mostly in slow or still pools and mature rice paddies. Peaceful, hardy and inexpensive, it has been mass-produced for many years and quality stock can be hard to find. The spotted 'leopard danio' is a spontaneous mutation of the striped form that also occurs in the wild.

The rosy danio, Danio roseus, is a small cyprinid from the Mekong basin in northern Thailand and Laos, also recorded in northern Myanmar. Colourful, hardy and usually cheap, it has proved very popular and is sometimes sold as 'purple passion danio'. It is very similar to D. albolineatus sensu stricto but has a slimmer body, shorter rostral barbels and no dark stripes on the rear half of the body. Many fish in the hobby are thought to be hybrids of the two.

The hikari danio, Danio sp. 'hikari', is a probable undescribed cyprinid from the Tanintharyi River drainage in southern Myanmar. First available in 2002, males and females were sold as 'Danio sp. hikari yellow' and 'D. sp. hikari blue'. DNA testing showed them to be one species, distinct from the very similar D. kerri, in which the central body stripe ends at the caudal peduncle. Only one population of D. kerri was sampled, so it could still be a colourful form of that species.

The black-barred danio, Danio sp. 'TW01', is a cyprinid apparently discovered near the coastal town of Gwa in Rakhine State, western Myanmar. It remains unclear whether it is an undescribed species or a geographical form of D. feegradei, which it resembles apart from lacking pale spots on the body. A dark marking on the caudal peduncle separates it from the superficially similar 'Inlecypris' maetaengensis and 'I.' shanensis.

The gold ring danio, Danio tinwini, is a tiny cyprinid from the Mogaung Chaung, an Irrawaddy tributary in Kachin State, northern Myanmar. Seen in the trade since 2003, it has been sold as 'Danio sp. TW02', 'D. sp. fire ring', 'D. sp. gold ring' and 'D. sp. spotted', among other names. Smaller than the similar D. kyathit and D. nigrofasciatus, it has spotted unpaired fins and much shorter barbels. Adults measure just 20 to 30 mm, so tankmates need choosing with that in mind.