Carp Species: 8 Types of Carp and How to Tell Them Apart

'Carp' is not one species. Wikipedia uses it for numerous freshwater fish in the family Cyprinidae, native mainly to Europe and Asia. The eight you are most likely to meet are the common carp, crucian carp, goldfish, koi, and four East Asian carps: grass, silver, bighead and black carp. South Asia adds the Indian carps catla, rohu and mrigal (Wikipedia). The common carp is also bred into scale forms, mirror and leather carp, that anglers treat as types of their own.

• Common carp (Cyprinus carpio): two pairs of barbels, one at the corners of the upper lip and one on the lower jaw; a serrated first spine in the dorsal fin; dark gold with large, shiny scales; a downturned mouth. Up to 120 cm and over 40 kg (Wikipedia). See common carp.
• Crucian carp (Carassius carassius): in the same genus as the goldfish, Carassius (Wikipedia).
• Goldfish (Carassius auratus): a domesticated fish from southern China (Wikipedia). See goldfish types.
• Koi: a coloured variety listed by Wikipedia under Cyprinus rubrofuscus. See types of koi.
• Grass carp (Ctenopharyngodon idella): a plant eater, typically 60 to 100 cm, up to about 2 m and 45 kg; it can eat up to three times its body weight a day (Wikipedia).
• Silver carp (Hypophthalmichthys molitrix): narrow, deep, flattened body with tiny silver scales and a scaleless head; eyes set far forward and low, below the mouth line (USFWS).
• Bighead carp (Hypophthalmichthys nobilis): large scaleless head, big mouth and eyes set very low, mottled silver-grey; typically about 60 cm, recorded to 146 cm (Wikipedia).
• Black carp (Mylopharyngodon piceus): brown to black with a bluish-grey to white belly; large scales with dark edges that look cross-hatched; throat teeth that crush mussels and snails. Adults are often around 33 lb and can pass 150 lb (USFWS).

These are not separate species but bred forms of the common carp. Wikipedia describes three:

• Mirror carp: a few large, mirror-like scales, often along the lateral line.
• Leather carp: virtually no scales except near the dorsal fin.
• Fully scaled carp: covered in scales like the wild fish.

Wikipedia says monks spread carp farming in Europe between the 13th and 16th centuries and that the mirror form originated in Germany. Wikipedia gives the mirror pattern as a recessive genotype. Wikipedia also records a Madagascar population, introduced from France in the early 20th century, that reverted to full scaling.

The US government's invasive species site lists four invasive carps, bighead, black, grass and silver, all imported from Asia for aquaculture ponds and spread into the Mississippi River system through floods and accidental releases. They are fast-growing, prolific feeders that out-compete native fish (invasivespeciesinfo.gov).

• Silver carp arrived in the 1970s and 1980s for fish farms and wastewater plants, to control algae, and have been listed as injurious wildlife under the Lacey Act since 2007 (USFWS).
• Black carp arrived in the same period in contaminated grass carp shipments and are also listed as injurious wildlife (USFWS).
• Grass carp reached the US in 1963; sterile triploid grass carp are now stocked in many states to control water weeds (Wikipedia).

The common carp, brought over in 1831, is not native to North America either (Wikipedia).

Silver carp jump when startled. USFWS says they leap up to 9 feet (3 m) when disturbed by boat motors. The US Geological Survey says they can jump as much as 10 feet in response to thrown rocks, passing trains or geese taking off, can weigh over 20 pounds, and have seriously injured many boaters. Bighead carp, the closest relative, stay underwater instead (Wikipedia), which is one quick way to tell the two apart on the water.

• Heaviest carp: 45.59 kg (100.5 lb), caught in 2013 (Wikipedia).
• British rod-caught record: 68 lb 1 oz (Wikipedia's Carp article).
• Oldest wild common carp: 64 years (Wikipedia).
• Grass carp: the fish with the largest reported farmed production in the world, over five million tonnes a year (Wikipedia).
• Bighead carp: 7.5% of all farmed freshwater fish, the fifth-highest production, rising from 15,306 tonnes in 1950 to over 3 million tonnes by 2013 (Wikipedia).

When you have a carp-like fish in hand, work through these checks:

• Barbels: two pairs on the mouth point to a common carp (Wikipedia).
• Eye position: eyes set low, below the line of the mouth, point to silver or bighead carp (USFWS; Wikipedia).
• Head: a scaleless head on a narrow, deep body is a silver carp; a very large head with blotchy colour is a bighead (USFWS; Wikipedia).
• Scale edges: dark-edged, cross-hatched scales on a dark fish suggest a black carp (USFWS).
• Scale pattern: a few big scales or none at all means a mirror or leather common carp (Wikipedia).

If you think you have caught a silver, bighead or black carp where they are not yet known, do not release it alive; photograph it and report it to your state fish and wildlife agency. FishLens can put a name to the photo first.

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