Danios & rasboras · waters

The waters behind the fish

Danios and rasboras are creatures of moving and standing fresh water — a monsoon hill stream in the Western Ghats, a flooded paddy on the Gangetic plain, a shaded leaf-litter brook in Myanmar, a tannin-black peat swamp in Borneo. Knowing which system a species comes from — its flow, temperature and hardness — is the foundation of keeping it well, and explains why a fast-water giant danio and a soft blackwater chili rasbora want such different tanks. Here are the freshwater systems that shaped 229 of the 233 species in this atlas.

India & the Gangetic plain

25 species

South Asia · India, Nepal & Bangladesh

The rivers, tanks and flooded paddies of the northern Indian plains — the Ganges and Brahmaputra basins. The home water of the original zebra danio (Danio rerio), the giant danio of the lowlands, the flying barbs (Esomus) of still ditches, and a wide range of plains Rasbora and Devario.

The Western Ghats

12 species

South Asia · peninsular India

The monsoon-fed hill streams and rivers of India's western mountains, a global freshwater biodiversity hotspot. The range of the endemic Devario of the ghats, the Malabar and canara danios, Rasboroides of the wet-zone lowlands, and many narrow-range species — a centre of danio conservation concern.

Sri Lanka

14 species

South Asia · Sri Lanka

The wet-zone rainforest streams and lowland tanks of Sri Lanka — a small island with a remarkable endemic fauna of Rasboroides, Horadandia, Devario and Rasbora, several restricted to a handful of shrinking drainages and threatened by habitat loss.

Myanmar — the Irrawaddy & Salween

59 species

South-East Asia · Myanmar & the eastern Himalaya

The rivers, hill streams, plateau lakes and leaf-litter forest pools of Myanmar and the eastern Himalayan foothills — the Irrawaddy, Sittaung and Salween. A danio epicentre: the celestial pearl danio of the Hopong plateau, the glowlight and many Danio and Devario, and the transparent Danionella of shaded forest brooks.

The Mekong & Chao Phraya

38 species

Mainland Indochina · Thailand, Laos, Cambodia, Vietnam

The great floodplains of mainland Southeast Asia — the Mekong, Chao Phraya and Mae Klong with their paddies, swamps and oxbows. The home of many Rasbora and Trigonostigma, the harlequin's relatives, the scissortail rasbora, and the Devario and Esomus of the slow lowland reaches.

Sundaland

78 species

Sundaland · Malay Peninsula, Sumatra & Borneo

The clear forest streams and acid blackwater peat swamps of the Malay Peninsula, Sumatra and Borneo. A centre of nano diversity — the chili and dwarf rasboras (Boraras), the blue neon Sundadanio, the harlequins (Trigonostigma) and many Rasbora and Trigonopoma of tannin-stained, soft Sundaic water.

East Asia

3 species

Subtropical East Asia · southern China, Taiwan & northern Vietnam

The subtropical rivers and hill streams of southern China, Taiwan and northern Vietnam — the northern edge of the danio range, with a scatter of Danio, Devario and Rasbora of the Pearl and Red River systems and the southern Chinese uplands.

Other Asian waters

4 species

South & Southeast Asia

Danios and rasboras whose recorded range falls outside, or spans, the named systems above — including many small, little-collected species known from a single stream, and widespread fishes carried far by stocking and the trade. Tropical-Asian freshwater hydrology is intricate and incompletely mapped, and danionin taxonomy is still moving.

← Browse the species index