Przewalskii's Naked Carp

Naked carp reach a maximum length of 48 cm (1.57 ft) and are typically 300–500 g (0.66–1.10 lb) at reproductive age. They have long, flat bodies and almost no scales except specialized ones embedded in the dermis near the anus and shoulder girdle, which gives them their common name, "naked carp". They grow relatively slowly and may take 7–10 years to reach reproductive size.

Feeding. They feed mostly on benthic zooplankton about 2 m (6.6 ft) below the surface, though they also feed on other aquatic invertebrates.

G. przewalskii is solely found in China—specifically it is endemic to Qinghai Lake and its tributaries in the northeastern region of the Tibetan Plateau. This is the largest endorheic saline lake in China; essentially, the lake retains water and does not outflow to other bodies of water. It is anadromous, living in freshwater and saltwater and returning to freshwater to spawn, with a migration cycle further outlined in detail in the following Reproduction and Migration section. Spatially, the naked carp is benthopelagic, found between bottom and midwater zones and in slow currents.

Reproduction and migration. The Qinghai Lake has a salinity of about 14 parts per thousand, meaning that the water is brackish. From April to July adults of the lake population migrate 40–50 km (25–31 mi) to nearby freshwater streams to spawn. Currently, the naked carp primarily uses only five freshwater rivers, the Haergai, Shaliu, Heima, Quanji, and Buha rivers. Much like salmon, they seek sandy gravel banks with slower currents to build nests. G. przewalskii shows a preference for pebble substrate during reproduction and sand substrate during pre and post spawning. When fish return to the lake, their electrolyte levels increase quickly to concentrations similar to Lake Qinghai's salinity, while urine flow, metabolic rate, and oxygen consumption all decrease drastically. …

Gymnocypris przewalskii is named in honor of naturalist General Nikolai Mikhailovitch Przhevalsky (also spelled Przewalski and Prjevalsky, 1839–1888), who collected the type species. The name was given by Karl Fedorovich Kessler, a 19th century Russian ichthyologist who processed a volume of Przhevalsky’s travelogue of Mongolia that includes Kessler’s description of the naked carp. The origins of the common name comes from Greek, in which gymnos = naked, and kyprinos = carp.