Grass Carp - Ctenopharyngodon Idella

About the Grass Carp.
The grass carp is a freshwater fish and member of the carp family Cyprinidae yet is more similar in appearance to the chub. It is native to large rivers located in Russia and Eastern China, particularly within the River Amur system, and has been introduced to many countries across the world as a natural and inexpensive means of aquatic weed control due to its nature of consuming massive amounts of plants and water vegetation.

Grass Carp Identification

Grass carp grow vary rapidly and are known to consume as much as three times their body weight a day in aquatic weeds and plants.

Their olive coloured body is torpedo-shaped and contains large silvery scales, which have a golden sheen. There are approximately 40 scales across the lateral line.

The fins are fairly short and rounded at the tip. The anal and dorsal fins both contain 8 - 10 soft rays and the caudal fin is deeply forked.

The head is large and the mouth is wide yet the lips are thin and firm. The mouth does not contain any teeth but two rows of sharp pharyngeal teeth are located at the back of the throat, which like a lawnmower, easily reduce the plants to small manageable pieces. Unlike other members of the carp family, the grass carp does not possess any barbules around its mouth.

Grass Carp Habitat

Grass carp were introduced into England and some parts of Wales during the 1970's as a biological form of weed control. They have been stocked in lakes, canals, ponds and backwaters of slow-flowing rivers with large amounts of vegetation.

However, grass carp need fast-flowing rivers and a certain water temperature to spawn, which are rarely found in the UK and therefore spawning does not take place naturally here.

In the UK grass carp are mainly located in the east of England in the counties of East Anglia and Lincolnshire.

As with other members of the carp family, during the summer months they can be found taking up the sun just under the surface of the water and retreat to deeper pools during the winter where the temperatures are slightly higher.

Natural Grass Carp Food

Grass carp introduced specifically to certain waters for the sole purpose of controlling weed growth are genetically modified into the triploid or sterile form, as the fertile diploid form is quite destructive to waters as it may displace native fish and eat essential vegetation required to maintain a harmonious habitat.

The sterile grass carp is known to consume hundreds of different type of plant matter. They are particularly partial to pondweeds, chara, waterweeds, water milfoil, coontail and bladderwort, which can all be harmful in an area if not controlled.

Grass carp do prefer certain types of plants and will consume those first before moving on to others that they do not like as much.

These fish have a habit of feeding from the top of the plant downwards, which is a huge advantage as the plants are not uprooted or destroyed and the natural habitat is maintained.

Due to the fact that grass carp are notorious herbivores, they often elude the angler as they do not take many baits offered to them.

Grass Carp Reproduction

Grass carp can only spawn in fast-flowing long rivers when water temperature reaches 25°C or over and for this reason they do not often spawn in the UK.

When the correct spawning conditions are in place the grass carp will lay thousands of eggs into the water, which then travel downstream until they hatch. These eggs actually weigh more than water and therefore a fast current is essential to keep them afloat. They generally hatch within two days, whilst they are floating along and are often able to travel hundreds of miles before they do so.

The Grass Carp's Vital Statistics