Koi, Cyprinus rubrofuscus Lacepède, in North Carolina

By the NCFishes.com Team

Common Carp, Cyprinus carpio (Figure 1), has swum in North Carolina’s waters since 1879 (Smith 1907). A long-held belief was that ornamental Koi (Figure 2) was merely a much-varied color morph of Common Carp. However, during post-processing of a photograph taken by the NCFishes team, we discovered that Koi are now considered a valid, separate species. Their Latin (scientific) name is Cyprinus rubrofuscus Lacepède 1803. Eschmeyer’s Catalog of Fishes recognized Koi as a valid species in June 2019 (https://www.calacademy.org/scientists/projects/catalog-of-fishes; Fricke et al. 2021). Up until then, Koi had long been synonymized with Common Carp.

Cyprinus carpio

Figure 1. Common Carp, Cyprinus carpio, collected from the Neuse River at SR 1224, Ferry Bridge Road, Wayne County, 35.357114/-78.136326, 30 March 2021. Total length not measured – large adult.

Cyprinus rubrofuscus

Figure 2. Koi, Cyprinus rubrofuscus, collected from the Dan River at SR 1416, Flippin Road, Stokes County, 36.54308/-80.411308, 28 September 2021. Total length was approximately 115 mm.

Koi can be separated from Common Carp by the following couplets (which has been modified and which will be updated in the next blog posting in “Minnow” Species (Families Cyprinidae, Xenocyprididae, and Leuciscidae) Diversity in North Carolina” (https://ncfishes.com/minnow-species-diversity-in-north-carolina/)):

The Latin name, Cyprinus rubrofuscus, refers to rubra meaning red and fuscus meaning dusky or dark, highlighting its golden-brown coloration (https://etyfish.org/cypriniformes10/, accessed 09/26/2021). The golden-brown coloration can vary significantly and Koi can have color combinations of bright gold, orange, silver, white, and black (Kottelat and Freyhof 2007 in Daniel et al. 2021; USF&WS 2020).

In 2019 and 2020 Koi were reported from North Carolina in iNaturalist from photographs taken at the Sarah P. Duke Gardens in Durham County (https://www.inaturalist.org/observations/26883974) and from two ponds in New Hanove County – Hugh McRae Park (https://www.inaturalist.org/observations/51348472) and a subdivision pond near Silver Lake (https://www.inaturalist.org/observations/47760310). The upper Dan River in Stokes County has long been known to harbor Koi. Most likely these fish escaped from aquaculture facilities within its upper watershed or from homeowner’s Koi ponds. Conceivably, Koi could be found in every river basin in North Carolina The distributional map found in Tracy et al (2020) for Common Carp undoubtedly contains records of Koi which had been recorded as Common Carp. Vouchered specimens will need to be reexamined to determine correct identifications.

The NCFishes Team would be interested in other sightings or collections of Koi from North Carolina’s waters. Please send all pertinent collection data and photographs to: fishesofnc@gmail.com.


Daniel, W. M., C.R. Morningstar, and J. Procopio. 2021. Cyprinus rubrofuscus Lacepède, 1803. U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=3294, accessed 09/26/2021).

Fricke, R., W.N. Eschmeyer, and R. Van der Laan. 2021. Eschmeyer’s catalog of fishes: Cyprinusrubrofuscus. (http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp, accessed 09/26/2021).

Tracy, B. H., F.C. Rohde, and G.M. Hogue. 2020. An annotated atlas of the freshwater fishes of North Carolina. Southeastern Fishes Council Proceedings No. 60. 198p. (Available at: https://trace.tennessee.edu/sfcproceedings/vol1/iss60/1)

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