Grass carp are a large freshwater fish found throughout the world. They are native to a small number of countries so their spread is testament to the hardiness of the species. They are an attractive fish for countries to stock as they are used to clear vegetation from areas of water. For anglers, they are a real treat when hooked and can be good fighters.
Grass carp (scientific name: Ctenopharyngodon Idella) is a freshwater species of the Cyprinidae family. This family dominates many of our freshwaters and includes other carp species such as the common, ghost and leather carp, as well as species including roach, bream and barbel. It is the only member of the Ctenopharyngodon genus.
In other parts of the world grass carp are also known as “white amur” (named after the Amur River which they are native to) which should not be confused with the white amur bream. In the UK they are simply known as grass carp.
Grass carp are incredibly valued for their ability to clean waters of excess aquatic vegetation. Governments around the world have imported grass carp for the purpose of cleaning waterways such as ponds, reservoirs and public waters.
Overstocking of grass carp can cause some issues where they have been introduced. In New Zealand, extensive research was conducted before importing the species. The research concluded that they are environmentally safe, there would be minimal damage to the fisheries and the removal of weeds by grass carp would be more less harmful than pesticides.
In some areas where grass carp are not native, “triploid” grass carp are introduced which are sterile. It is hoped that the species will not spread and become invasive by introducing the triploid variety.
There is some interest in grass carp among aquarium enthusiasts, purely for their looks. There is even a variety of albino grass carp which are a pinky white colour and have red eyes which also appeal to those with aquariums.
Grass carp are extensively farmed worldwide. The largest reported yield is five million tonnes yearly. The reasons for farming this species is firstly as use in clearly aquatic vegetation. The second reason is for farming the species is for as use as a food fish as it is popular to eat grass carp is some countries.
Grass carp are consumed as food in some countries. They are extremely popular in China, where the fish are native. They are rated as highly as salmon in China and there are a large variety of recipes for grass carp including steamed and fried fish.
They are not popular as eating fish in other countries such as the UK, where the fish are thought to taste grassy or muddy.
Distribution and Habitat
Grass carp are native to east Asia. They are native to Russia, China, and Brunei. It seems strange that such a widespread species originates in so few, albeit large, countries.
Grass carp are extremely common across the world. They have been exported throughout Europe in countries including Belarus, Belgium, Germany, the UK and Greece. They have been imported to the Americas including countries such as Canada, Cuba, Panama, the USA and Honduras.
They have been imported to African countries including Egypt, Kenya, Mauritius, Morocco and Tunisia. They have also been exported to other Asian countries where they are not native, including India, Pakistan, Japan, Philippines and Vietnam.
In the USA, grass carp are known to inhabit at least 45 states. They have spread rapidly and are considered as invasive pests. The reasons for the rapid spread include the stocking of the fish by different government agencies in various locations, release by people into the waterways and escapees from ponds and aquaculture facilities.
In some states there are restrictions on bringing the species into the state and it is prohibited to stock or hold the species. Oddly, the importation to different states continues as a use of biological control.
In the UK, the species are unable to breed as they are sterile. The Environment Agency of the UK still regulates the introduction of this species to ensure that it cannot spread throughout the waterways.
Grass carp inhabit freshwater lakes, ponds and rivers. They prefer slower moving or still waters so will inhabit the slower moving rivers. They have been introduced to reservoirs and other still water environments where they tend to thrive. They will seek out heavily vegetated areas as they search for food.
Grass carp are a hardy species. They can survive in water with a low oxygen content and can survive in water with some salinity. They can tolerate cold and warm temperatures – between 0 and 33 degrees Celsius.
Grass carp are long and slender and have torpedo shaped bodies. They have large, flat heads with stubby snouts and upturned mouths. The mouths are located at the end of their heads rather than under. They have surprisingly small eyes for a fish of their size.
As with common carp, they have large scales but do not have scales on their heads. Unlike common carp, they do not have thick and rubbery lips as grass carp’s tend to be firm and not at all fleshy. Again, unlike common carp they do not have barbules on their mouths. Grass carp do not have teeth in their mouth but have powerful pharyngeal teeth which crush food before swallowing.
Grass carp tend to be dark grey, dark bronze or an olive green colour on their backs. Their flanks is lighter in colour and is a silver colour towards their bellies. They have creamy white bellies. They are an attractive fish when looked at from the side.
The fins of grass carp can vary in colour. There may be fish with light grey fins but you are more likely to find fish with dark grey or black fins. Male grass carp have more extended and thicker pectoral fins whereas the females have shorter pectoral fins which are spread out.
While carp are related to common carp, they are more akin to chub in appearance.
Grass carp are large fish, and they can grow to enormous sizes. On average they grow between 8 to 20lb (approximately 3.5 to 9kg). The British record stands at a huge 44lb 8oz which must have been an incredibly powerful fish.
Grass carp are slower growing in the UK where the climate is cooler and are thought to gain 1-3lb in weight per year. In the warmer water of France and other warmer countries in Europe grass carp can grow up to 10lb per year and 65lb specimens have been caught in France.
The average length of grass carp ranges between 24 to 40 inches (approximately 0.6 to 1m) however there are likely to be larger specimens in prime habitats. Grass carps’ lateral line scale count is 42 – 43.
Grass carp are shorter lived than other members of the carp family as they reach on average 10 to 15 years of age.
How they Feed
Many people think that grass carp are herbivorous and only eat aquatic vegetation. Whilst aquatic vegetation does form a large part of their diet, they are in fact omnivorous.
Grass carp patrol the waters in shoals in search of food. They will usually be found in the deeper areas of water and they can sometimes be spotted swimming near to the surface.
Grass carp can eat a tremendous amount of food. It has been said that they can eat more than their body weights daily. They will eat more vegetation when they are young however as they age they will eat vegetation but supplement this with molluscs, crustaceans and invertebrates.
Grass carp are unable to spawn in the UK and large parts of Europe as the sterile triploid fish are imported. The female fish will be conditioned to spawn and will actually release eggs, however these remain in the water unfertilised.
Grass carp ordinarily spawn when the water temperature reaches a warm 22 to 27 degrees Celsius. The females can lay between 50,000 to 100,000 eggs depending on the climate and health of the fish.
The females lay their eggs which are slightly buoyant but heavier than the water. The fertilised eggs will develop on their journey downstream. The eggs which reach the backwaters to hatch and the juveniles will feed on the abundant vegetation in the area.
How to Catch Grass Carp
Similar to other carp varieties, grass carp can grow to large sizes and are muscular and powerful. Many fisheries will stock grass carp, usually on a catch and return basis. Grass carp can be wary and sometimes difficult to catch, which makes it more rewarding when you do hook one of them.
Grass carp will be found in still waters amongst thick vegetation. Warmer months are the best time to catch grass carp, from the months of April to October. In the sunny weather grass carp can be seen fishing on the surface and this can be a good place to catch them.
In terms of bait, you can use many similar baits which you can use for carp. If you are looking to feed at depth, try sweetcorn, boilies (fruity flavours work well), peanuts, tiger nuts, hemp and maggots. If you are looking to fish on the surface try, bread, dog biscuits and boilies or pellets which float (again try to get fruity flavours).
Grass carp can be different to other carp when hooked. They seem more like bream when hooked as they allow themselves to be reeled in easily before making a frantic run for it.
The tackle required for grass carp is similar to that for carp, however their weights vary so take this as a guide and try to match your tackle to the size of fish you are looking to catch.
Generally, a good rod with a 2lb test curve fitted with a fixed spool reel should do the trick. You will need at least a 10lb main line and 4lb+ hook length (6 – 24 inches) with a size 4 – 12 hook, which depends on your bait.
You could try ledgering or fishing on the surface which should meet with good results. For ledgering, fish just off the bottom and take a few different baits to try.
If you are fishing on the surface, bread or dog biscuits work well but will disintegrate, so if you are looking for something which will last longer a floating boilie would do well.
Grass carp are notorious for thrashing around on the bank when caught so the utmost care must be taken when handling the fish.
They can be a deceptive fish to catch as they will follow your line towards the bank which can make you think that you’ve caught a tiddler. When they see the landing net they may then dart alarmingly so be prepared to allow them to take line.
Once you bring your catch in to land, use a good landing net and give the fish some time to relax in the water. Lift the fish away from the banking so that it is not caught on anything sticking out. The fish have been known to thrash around and fall out of the landing net so be aware for this.
Lift the grass carp directly onto a good unhooking mat. Try to put the mat on flat land away from the banking. Try not to lift too high from the ground in case you stumble and drop the fish. The hook will usually be found in the lips, however have forceps or a disgorger on hand in case it is deep hooked.
You can weigh the fish but not too high above the ground. Be careful here as the fish can flap without warning to be sure to protect yourself and the fish.
You can also take photos but do not stand high in case you drop the fish. Keep the fish wet, it is good to do this frequently if you intend to weigh or take pictures.
If you would like more information on how to fish for grass carp, or would like some further information on angling techniques, check out our fishing tips page for more information!