Carassius auratus, Conservation

Carassius auratus View in CoL View Figure

Common name. Goldfish.

Diagnosis. Distinguished from C. carassius in West Asia by: ● flank silvery, golden-green or reddish / ● last simple anal and dorsal rays strongly serrated / ● 38–52 gill rakers / ● 26–33 total lateral-line scales/ ● free edge of dorsal concave or straight / ● usually 5½ branched anal rays / ● peritoneum black. Size up to 350 mm SL.

Distribution View Figure . Widespread in West Asia. Most non-native Carassius in West Asia have mitochondria belonging to this species. Reportedly native to East Asia, from Amur to Xi Jiang drainages in Russia, China, Korea, and Japan, several species appear to be confused under a single name, as evidenced by available data on Japanese populations. Domesticated in China more than 1000 years ago, introduced to Japan in 16 th century and imported from Japan to Europe in 1611 (Portu- gal),1691 ( England),and 1755 ( France) and subsequently intro- duced throughout West Asia,Europe, and most of the world.

Habitat. A wide variety of still waters and moderately slow-flowing rivers. Very tolerant of low oxygen and pol- lution. Usually associated with submerged vegetation or periodic flooding. Spawns on shallow, warm banks, on sub- merged vegetation or roots.

Biology. Only diploid populations known. Spawns first time at 1−2 years. Spawns June−July when temperatures reach 15−20°C. Juveniles need high temperatures to grow. Single females spawn with a few males in dense vegetation. Eggs are sticky and attached to water plants or other submerged objects. Usually lives for about 20 years in artificial con- ditions. Omnivorous, feeds mainly on plankton, benthic invertebrates, plant material, and detritus.

Conservation status. Non-native; introduced as a weed with stocked carp.

Further reading. Kottelat 1997 (systematics); Szczerbowski 2002 (biology); Kottelat & Freyhof 2007 (distribution, biology).