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The Crucian Carp: A Fascinating Species Guide

The Crucian Carp: A Fascinating Species Guide

Crucian carp are fascinating and mysterious fish! This is a species unlike any other, with many talents and secrets. Even though I have caught plenty of crucian carp over the years, this small fish never stops to surprise or amaze me. So much so, that I decided to write an article about it.

The crucian carp is one of the smallest members of the carp family Cyprinidae. This fish has developed advanced survival skills, as it, for example, can increase its body depth to reduce the risk of predation, and is able to survive the coldest of winters and hottest of summers with ease.

Continue to read this article, to learn all the amazing and interesting facts and mysteries about the crucian carp.

What Do Crucian Carp Look Like?

a big crucian carp on an unhooking mat that an angler caught on the lift method
Courtesy of Elis Wessmark

The crucian carp (Carassius carassius) is a small to medium-sized fish that is completely covered by scales. Its appearance reminds of that of the common carp, but the crucian is a much smaller and often much deeper fish. Unlike the common carp, crucians also lack barbels.

In waters with a lot of predation, the crucian carp’s body is an almost perfect disc shape, making it appear like a plate. In extreme cases, its body depth can exceed its body length.

Depending on the type of venue and clarity of the water it inhabits, its coloration can be anything from golden or bronze, to dark brown, and sometimes even blackish.

The crucian has a disproportionately long dorsal fin that can cover the entire second half of its back, as well as beautiful, well-rounded pelvic and pectoral fins.

Both its mouth and eyes are rather small when compared to the rest of its body size, which, on average, measures 8-15 inches.

Survival Skills of The Crucian Carp

The crucian carp is an awe-inspiring creature that evolution has granted with incredible survival skills. Here are the most amazing of them:

Predation Protection

As stated above, the crucian carp can change its body shape if there is a risk of predation in the venue it occupies. In practical terms, the crucian has the ability to form its body into a much deeper shape, making it round and disc-like.

This body shape is extremely difficult for e.g. pike or zander to swallow a crucian, increasing the crucian carp’s survival rate immensely.

This changed shape is then passed on to the next generations, often reshaping an entire fish population in the process.

The crucian’s hard and tough flesh is another natural protection against hungry predators, as they are not easily chewed on.

Oxygen Depletion

During harsh and long winters, many lakes and ponds can run critically low on oxygen levels. Many other fish species do not survive such an event. The crucian, on the other hand, is a true survivalist when it comes to oxygen depletion as well!

When the oxygen levels are low and the ice sheet on the lake is thick, the crucian simply turns its respiratory system to an anaerobic state, meaning that it does not require oxygen for breathing.

It can remain in such a state for up to 4 months. As a side product, its body starts to produce ethanol, which is yet another marvelous and mystifying skill of the crucian.

Heat and Drought

Oxygen depletion can also occur during very hot summers, during which the crucian will react in exactly the same manner, but only for a shorter period of time, compared to winter.

When the water gets too hot, or too low, it can also bury itself deep into the lake bed’s cooler mud sediment. Here, they can remain for several weeks, waiting for cooler weather and rainfall to draw in and replenish the venue with fresh and oxygenated water.

Where Do Crucian Carp Come From?

a big crucian carp in a landing net that an angler has caught on a pair of sweetcorn
Courtesy of Anders Groenlund

While the earliest records about crucian carp go back to the Chinese East Han Dynasty around the year 100 A.D., this fish is also a native species to Europe.

It can be found all over the European and Eurasian continent, from the Eastern parts of Russia to the British Isles, and from the south of France to the northern parts of Scandinavia. No one really knows how the crucian got to Europe, however.

A study even found that the crucian carp is a native English species and has not been introduced to English waters.

In another interesting governmental report from 1910, researchers have found crucians in the U.S. state of Illinois, stating that there could be other U.S.-based populations of crucians.

These are just a few more of the many mysteries surrounding the crucian carp.

In What Types of Venues Can You Find Crucian Carp?

lots of crucian carp feeding bubbles on lake surface
Courtesy of Tim Heighes

Crucian carp can be found in both still and running waters and generally prefer smaller ponds and lakes, as well as very slow-moving rivers that are rather shallow.

Such venues should have rich vegetation, in the form of reeds, weeds, lily pads and/or overhanging trees, as crucians tend to seek out cover and shady areas.

The bottom of crucian venues should be muddy or silty because crucian carp are absolute bottom feeders and scan soft bottoms for food.

When feeding, they produce copious amounts of bubbles that both originate from their gills from filtering out mud and dirt, and from the bottom itself, as the feeding crucian are releasing trapped gas from it.

How Do You Fish for Crucian Carp?

an angler on a forest lake holding a giant crucian carp that he has caught on the float

The crucian is a very careful fish that is rather shy and does not feed excessively. This, in combination with its main location being close to vegetation along a venue’s margins, suggests that anglers should resort to both stealthy and very delicate fishing methods.

The best of which would of course be float fishing with extremely light tackle.

As the angler does not have to cast out his or her rig very far (often only a couple of yards off the bank), fishing with floats around 1g is definitely a good option, as there will be minimal resistance for the crucian.

Additionally, the mainline, hooklink, and hook should also be as thin and small as possible. A 6lb mainline, coupled with a 4lb fluorocarbon hooklink and a size hook 12-14 is a very good setup for crucian carp.

The crucian’s preferred baits include maggots, small lobworms, sweetcorn and soft pellets. Groundbait feeding and loose feeding with particles should be kept to a minimum to avoid overfeeding the crucians.

How Big Can Crucian Carp Get?

While its average weight is somewhere between 2 and 4lb, there are countries and venues in which crucian carp of over 6 to 8lb have been observed or caught.

In the UK, they tend to reach a maximum size of 4lb, while they can grow to well over 6lb in the much colder Scandinavia. And in countries such as Germany or the Netherlands, they instead grow to real monster sizes of over 8lb.

The British record is held by two anglers simultaneously, as they managed to catch the same crucian with the exact same weight in one and the same venue. Hence, Michael James and Stephen Frapwell hold the current British crucian carp record of 4lb 10oz.

The fish was first caught on May 4th 2015, and then again on May 10th 2015 at Johnsons Lake (Milford, Surrey).

The world record crucian carp is a stunning fish that was caught in the Netherlands back in 2009. This massive fish measures an unbelievable 22 inches and weighed in at a whopping 9lb 8oz (4.3kg).

Personally, I have not read about a crucian even coming close to such a weight, which suggests that this record might last for a very long time.

By the way, if you want to read up on all the different types of carp, make sure to also read this article I wrote: What Types of Carp Are There? (A Species Guide)

What Is The Maximum Age of Crucian Carp?

It is said that crucian carp can reach an age of about 10 years, with a maximum of 15 years.

The verified world record age of the crucian carp is however a stunning 30 years!

Based on that, one can reason that an age of 10-15 years should be considered more of an average life span, as it can be assumed that there is simply too little data on the life span of crucian carp.

What Does Carassius Mean?

The crucian carp’s Latin name Carassius carassius actually means goldfish, which is probably linked to the crucian’s often golden or bronze coloration.

The crucian’s close relative, the goldfish, also has the word carassius in its name; Carassius auratus. Many sources state that the goldfish is a cultivated breed of wild crucian carp, which would explain their common features and appearances.

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Featured image courtesy of Leif Krause

  1. Jack Pells says:

    Beautiful pictures

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