Amur basin

The Chinese false gudgeon, Abbottina rivularis, is a small bottom-dwelling cyprinid native to China, the Korean peninsula and southern Japan. It has been widely introduced elsewhere, including the Mekong and Salween basins, Taiwan, Turkmenistan and Kyrgyzstan, and is considered invasive. It has started to appear in the aquarium trade and should never be released into natural waters outside its native range.

The giant Chinese bitterling, Acheilognathus macropterus, is a bitterling from China, the Korean peninsula, northern Vietnam and southeastern Russia. It has been introduced to Japan and is considered invasive there. Typical adults are 100 to 150 mm, and it appears in the trade only irregularly. Like all bitterlings it spawns in living unionid mussels, and its wide range suggests it may be a group of closely-related species.

The roundtail paradise fish, Macropodus ocellatus, is a labyrinth fish with an enormous range in China, Korea and Japan, north to the Amur River. It lives in ditches, rice paddies, marshes and river backwaters, where winter can freeze the surface and drop the water to 3 °C. It is sometimes referred to as M. chinensis in older literature, a name now considered a synonym of M. opercularis. Males are territorial when breeding and build bubble nests.

The large-scaled loach, Misgurnus dabryanus, is a 'true' loach from the Yangtze and Pearl rivers in China, plus Taiwan and the Amur in Russia. It is sold regularly in the hobby but almost always labelled as or mixed in with M. anguillicaudatus, from which it differs in its high adipose crests on the caudal peduncle and the lack of a dark spot at the caudal-fin base. It spends some of its time completely buried, so it needs a soft, sandy substrate.

The northern snakehead, Channa argus, is a large snakehead native to eastern China, southeastern Russia and the Korean peninsula. Growing to 850 mm, it is largely unsuitable for the home aquarium given its size and natural behaviour. Introduced populations, first intended for aquaculture, are now established in Japan, the United States, central Asia and parts of eastern Europe.

The grass carp, Ctenopharyngodon idella, is a large cyprinid native to the Amur River system in eastern Russia and northeastern China. Adults typically reach 800 to 1200 mm, making it a wholly unsuitable aquarium subject, though an albino form is traded. Widely introduced for aquaculture and weed control, it has caused serious damage to natural waters, and unwanted fish should never be released.

Elopichthys bambusa is a large predatory cyprinid of eastern Asia, from the Amur River in Russia to the Lam drainage in northern Vietnam. Growing to 2 m and 40 kg, it is entirely unsuitable for the home aquarium, though young individuals appear in the ornamental trade on an irregular basis. The only species in its genus, it is an important food fish over much of its range.

The barbel steed, Hemibarbus labeo, is a cyprinid widespread in eastern Asia between the Yangtze and Amur river basins. A predominantly riverine fish of clear, well-oxygenated running water, it forms schools just above the substrate as an adult, and some populations make annual spawning migrations. Adults lack dark spots on the body and have a long snout and well-developed lips.

The spotted steed, Hemibarbus maculatus, is a cyprinid widespread in eastern Asia between the Yangtze and Amur basins, including Taiwan and Hainan. It has 7–11 large blackish spots on each flank and a deep body with a clearly convex dorsal profile. A riverine fish of clear, well-oxygenated running water, it breeds in May and June, depositing its eggs among aquatic vegetation. It has probably been introduced to Vietnam and Laos, or records from there represent another species.