Prussian carp

What it is

The Prussian carp is a deep-bodied and robust member of the cyprinid family. It typically reaches lengths between 10 and 35 centimetres, though it can grow up to 45 centimetres. The fish usually displays a silvery colour, sometimes with a faint golden hint, which distinguishes it from the more burnished gold appearance of the crucian carp. Its scales are larger than those of its relative, with 27 to 32 scales along the lateral line. The tail fin is also more deeply forked. This medium-sized fish does not exceed a weight of 3 kilograms.

Where it lives

Originally found in Siberia or central Europe, this species has been introduced to many other regions. It now inhabits lakes, ponds and slow-moving rivers across Europe, North America and Asia. In European Russia, it has become particularly abundant in the Volga and Kama rivers. It thrives in coastal areas that are overgrown with aquatic vegetation. Its ability to adapt to various freshwater environments has allowed it to establish strong populations far beyond its native range.

How it lives

This fish is omnivorous and feeds on a varied diet. It consumes plankton, invertebrates, plant material and detritus found in its environment. As an invasive species, it spreads rapidly in new areas. Recent studies suggest that waterfowl may help disperse its eggs. Although birds digest most eggs they eat, a small proportion survive passage through the digestive tract and hatch later. This process, known as endozoochory, could be a significant mechanism for the spread of this invasive fish in freshwater systems.

Breeding and life cycle

Prussian carps reproduce through a process called gynogenesis. In this method, sperm from a male is required to trigger the development of the egg, but the male genetic material does not contribute to the embryo. Females essentially steal sperm from related species to activate their own unfertilized eggs. This allows them to produce offspring without incorporating male DNA. Combined with the production of hundreds of thousands of eggs per spawning event, this reproductive strategy enables rapid population growth and spread.

Fish and people

The Prussian carp is regarded as a highly invasive species in areas outside its native range. Its rapid reproduction and spread pose a conservation concern for freshwater biodiversity. While it is not highlighted for food or aquarium use in the provided text, its ecological impact is significant. The potential for birds to disperse viable eggs further complicates management efforts. Scientists note that if endozoochorous dispersal is proven under natural circumstances, it represents a serious challenge for controlling invasive fish populations.

Status and threats

The species is classified as highly invasive in regions where it has been introduced. Its ability to reproduce via gynogenesis and its high fecundity allow it to outcompete native species. The discovery that bird digestion may aid in spreading viable eggs adds to concerns about its unchecked expansion. This dispersal mechanism could threaten freshwater biodiversity by allowing the fish to colonise new water bodies unexpectedly. Conservationists view this potential vector as a significant risk to local ecosystems.

Relatives and look-alikes

The Prussian carp belongs to the genus Carassius, which includes the crucian carp and the goldfish. It closely resembles the crucian carp but can be distinguished by its larger scales, deeper forked tail and silvery rather than golden colour. It is part of the subfamily Cyprininae, which also contains barbs. These related species share similar body shapes and habitats, leading to occasional confusion between the Prussian and crucian carps.

Questions people ask about Prussian carp

Good reading and sources

• Prussian carp on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data