Loaches · waters

The waters behind the fish

Loaches come from very different waters — a cool, fast Chinese hill stream over polished stone, a Bornean peat swamp stained like tea, a warm Mekong floodplain, a Himalayan torrent thin with cold, a sluggish European lowland ditch. Knowing which system a species comes from — its temperature, flow and oxygen — is the foundation of keeping it well, and explains why a hillstream loach and a lowland kuhli want such different tanks. Here are the freshwater systems that shaped 1378 of the 1405 species in this atlas.

East Asian rivers & streams

479 species

Temperate East Asia · China, Japan, Korea & Taiwan

The great rivers and hill streams of temperate East Asia — the Yangtze, the Pearl and the rivers of Japan, Korea and Taiwan. Home to the Chinese botiids (Sinibotia, Leptobotia, Parabotia), the flattened hillstream loaches of the southern Chinese torrents (Beaufortia, Pseudogastromyzon, Gastromyzon), and the hardy weather/dojo loach (Misgurnus anguillicaudatus) of the paddies and ponds. Much of this water is cool and seasonal — many of these loaches are coldwater or subtropical, not tropical fish.

Mainland Southeast Asia

309 species

Indochina · the Mekong, Chao Phraya, Irrawaddy & Salween

The floodplain rivers, forest streams and hill torrents of mainland Southeast Asia — the Mekong, Chao Phraya, Irrawaddy and Salween. The richest loach country in the trade: the botiids Yasuhikotakia, Syncrossus and Ambastaia (including the dwarf chain loach), a wealth of Schistura brook loaches, the reticulated hillstream loach Sewellia and its kin in the Annamite torrents, the horseface loach Acantopsis of the sandy lowlands, and the Chinese algae eater (Gyrinocheilus aymonieri). Conditions run from soft, fast forest streams to warm lowland rivers.

Sundaland & the Malay archipelago

166 species

Sundaland · the Malay Peninsula, Sumatra, Borneo & Java

The forest streams, blackwater peat swamps and clear hill torrents of the Malay Peninsula, Sumatra, Borneo and Java. This is the home of the clown loach (Chromobotia macracanthus) of Borneo and Sumatra, the eel-like kuhli loaches (Pangio) of the leaf-littered forest streams, the sucker-mouthed Gastromyzon and Homaloptera of the Bornean rapids, and the odd little Barbucca and fork-tail Vaillantella. Water ranges from acidic, tannin-stained blackwater to cool, fast, clear rock streams.

The Indian subcontinent & Sri Lanka

159 species

South Asia · the Ganges, the Western Ghats & the island streams

The rivers, hill streams and paddies of India, Sri Lanka, Bangladesh, Nepal and Pakistan. The realm of the yoyo loach (Botia almorhae) of the Ganges drainage and its many banded Botia cousins, the zebra loach (Botia striata) and the Mesonoemacheilus brook loaches of the Western Ghats, the Balitora hillstream loaches of the fast foothill rivers, and the widespread Lepidocephalichthys and Acanthocobitis of the lowlands. Soft, cool hill water through to warm lowland river.

The Himalaya, Tibetan Plateau & Central Asia

74 species

High Asia · the Tibetan plateau, the Himalaya & the inland basins

The cold, fast, thin-aired streams of the roof of the world. This is the country of Triplophysa — a huge genus of stone loaches adapted to high-altitude Tibetan and Central-Asian waters, some living above 4,000 m — alongside high-mountain Schistura and Nemacheilus and the loaches of the closed inland basins (the Tarim, the Amu Darya and Syr Darya). Little-studied, cold-adapted fish, most of them of interest to science rather than the aquarium, included for completeness.

Western Asia, Europe & the Mediterranean

191 species

The West · Europe, Anatolia, the Middle East & the Maghreb

The temperate rivers, lakes and springs of Europe, Anatolia, the Middle East and North Africa. Home to the spined loaches (Cobitis and Sabanejewia) of the Danube, the Volga and the Mediterranean drainages, the European weather loach (Misgurnus fossilis) of the sluggish lowland waters, the stone loach (Barbatula barbatula) of clean upland brooks, and the Oxynoemacheilus and Paracobitis of the Anatolian and Middle-Eastern streams. Almost all are coldwater or cool-temperate fish, and several are of real conservation concern.

Other waters

27 species

Across the range

Loaches whose recorded range falls outside, or spans, the named systems above — including widely-distributed species and several little-collected stone & brook loaches known from a single stream. Cobitoidea is vast and incompletely mapped, and the family-level taxonomy is still moving, so some species sit here until their range is pinned down.

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