They like to drink some crayfish with beer, take care of others in aquariums, but few people recall that these creatures managed to survive for 130 million years, almost without changing their structure. The only thing that distinguishes them from their ancient counterparts is their size. During the Jurassic period, some types of crayfish reached 3 m in length and could stand up for themselves.
Today, in the ranks of crustaceans, there are about 55,000 representatives of very different lengths living in sea or fresh water, and some of them prefer to be land.
Gourmet History
People have used crayfish since the time of Antiquity, but then they were not served on the table in the form of a delicacy. Obviously, healers and healers of the ancient world knew about the beneficial properties of shells, as they made drugs from them from the bites of poisonous insects.
The first mention of the fact that river crayfish are a delicious dish was recorded in the 16th century, when one of the Swedish kings accidentally tasted them. Immediately, a decree was issued so that the peasants would catch and deliver them to the royal table, but dare not eat them themselves on pain of the death penalty.
Imitating the king, the Swedish nobles did the same, although the royal decree was bewildering among the poor people. They did not consider crayfish to be food and were content with them only during the famine, which was extremely rare in this country.
In modern Sweden, there is even a national holiday, Crayfish Eating Day, when people gather in large companies, cook these arthropods and drink strong drinks.
Today, some types of crayfish (photo shows this) are considered a delicacy and are not just served with beer, but are prepared from them soups, salads, stewed with vegetables, made sauces from them and even fried.
Their meat is considered to be one of the most environmentally friendly, despite the fact that they are sewage collectors and "orderlies" of water sources. This is due to a balanced, self-cleaning organism, given to it by nature.
River Arthropods
There are different types of crayfish, but this name is not entirely accurate, as they live in swamps, and in ponds, and in lakes, and in artificial reservoirs. It is more correct to use the concept of “freshwater”.
All representatives of crustaceans living in fresh water have the same structure:
- their body can reach a length of 10 to 20 cm;
- the upper body is called the cephalothorax;
- they have an elongated and flatter abdomen;
- the body ends with the caudal fin;
- they have 10 chest legs and gills.
The most famous types of freshwater crayfish are:
- Broad-toed (Astacus astacus) lives in water bodies of Western Europe and high-mountain rivers of Switzerland, prefers places with a temperature from +7 to +24 degrees Celsius.
- Fine-fingered (Astacus leptodactylus) can live both in fresh running or standing water, and brackish with maximum heating up to +30.
These types of crayfish are not suitable for keeping in aquariums, as they are very demanding in care, especially for filtering water and temperature condition.
Florida Cancer
Well-known to many aquarists, red Florida cancer can actually be black, white, orange, or even blue. It lives both in swamps and flowing rivers, and in flood meadows, and as the water decreases, it "goes" into deep burrows underground.
These are the most undemanding types of crayfish in composition and quality of water. Their appearance is well known to residents of not only marsh Florida, but also Europe. Its distinctive feature is the red spikes located on the claws.
This small arthropod (body length up to 12 cm) can easily tolerate water temperature from +5 to + 30 degrees and multiply year-round in the aquarium, laying up to 200 eggs. Incubation continues for 30 days, and at this time the temperature in the aquarium should be maintained at +20 ... + 25 degrees.
Red swamp cancer coexists well with fish, but it should be remembered that 1 pair will need an aquarium for 100 liters of water.
Blue Cancer from Cuba
Cuban blue crayfish may have other colors, as this directly depends on the natural conditions in their habitats and the color of the parents.
This tropical arthropod species lives in Cuba and Pinos. It has a small body up to 12 cm (excluding claws) and has a completely peace-loving character, so it can be kept in aquariums with moving or large fish.
The fact that this cancer is unpretentious and reproduces well in captivity makes it a favorite of many aquarists. For 2 or 4 representatives of blue Cuban cancer, a 50 liter capacity with good ventilation and water filtration will be required.
A female of this species can lay up to 200 eggs at a time. For this to happen, it is better to transfer the crayfish before pairing into a smaller aquarium so that there is no interference from the "neighbors". Incubation lasts 3 weeks, during which the water temperature should be +25 degrees.
Marine arthropod
The most popular among gourmets is lobster meat. These marine crayfish species differ from their freshwater counterparts solely in size and weight. They have a strong chitinous shell, which young individuals change as they grow older.
Shedding a lobster takes from 2 to 4 weeks, during which time it is defenseless and forced to hide from its enemies in secluded places. The process of getting rid of tight coverage is interesting. The shell bursts on the back of the lobster, like clothes cracked at the seams. To free itself, the cancer has to back out of it, taking one leg after the other.
The female lobster lays up to 4000 eggs on its tail, after which the male fertilizes them. The incubation period lasts 9 months, during which the eggs remain on the mother’s body. Individuals that survived 25 molts are considered ready for mating and eating.
European, Norwegian and American lobster species are well known to foodies. The cost of their tender, healthy, dietary meat starts at $ 50 per kilogram, and 100 years ago it was used as bait for fishing.
Land Arthropod Representative
If you think about the question, what are the types of crayfish, then few will remember that there are unique individuals that can climb trees.
These are coconut crayfish (Birgus latro) that live on the islands of the Indian and Western Pacific Oceans. During the day, these amazing creatures hide in the foliage of palm trees, and at night they go down to pick up fallen fruits or carrion from the ground. The islanders call these hermit crabs thieves, as they often pick up everything that is bad, in their opinion, lies.
Although coconut cancer spends most of its life on earth, it begins its life in bodies of water, where females lay eggs, from which small and defenseless crustaceans emerge. To survive, they are forced to look for a protective coating for their bodies, which most often becomes some kind of shell.
After the young growth, the crayfish go outside and can no longer return to the aquatic environment, as their gills atrophy, and the ventilated lungs become the respiratory organs.
Those who want to see these unusual creatures will have to go to the tropical jungle at night. Their meat is considered a delicacy and an aphrodisiac, but the “hunt” for them is extremely limited.
Rare crustaceans
The rarest types of crayfish that can live in aquariums are called apricot. They live in Indonesia and can be either a delicate orange or blue, which is extremely rare.
They are small in size, males rarely grow to 10 cm, and the female is 8 cm long.To keep them in aquariums, you should not only make sure that the temperature regime is kept within +25 degrees, but the bottom is correctly formed.
These cancers love fine gravel, sprinkled with bamboo, almond or oak foliage, which also serves as a good antiseptic. Numerous shelters in the form of snags, metal pipes and artificial houses will not interfere. For the most part, Orange Papua New Guinea lobster is a non-aggressive vegetarian, but it is still not recommended to “hook” small fish to it.
The largest freshwater arthropod
The largest types of crayfish that live in fresh water, originally from Tasmania. In rivers in the north of this Australian state, individuals are found that reach 60-80 cm in length and weigh from 3 to 6 kg.
Their favorite habitat are rivers with a calm flow, good ventilation and air temperature of +18 degrees. Depending on which river these giants live in, flat or mountainous, they can have a color from green and brown to blue.
Since Astacopsis gouldi live to be 40 years old and are considered among their congeners as long-livers, all their life processes are somewhat delayed. For example, males are ready for breeding at only 9 years old, and females at 14 years old, with mating at them once every 2 years, and the incubation period lasts from autumn until the summer of next year. In this regard, it is customary for the Tasmanian giants to keep a harem of females of different ages.
Heraxes
Another representative of the Australian rivers is Herax crabs. Surprisingly, these arthropods, numbering many species, include individuals with completely different dimensions. So, some of them can be 40 cm in length and weigh up to 3 kg, while others grow up to 10 cm and are placed in aquariums up to 20 liters. Another home for these freshwater rivers are New Guinea.
It is not difficult to create conditions for keeping Heraxes in the aquarium. They love warm water and the ability to rummage in the ground, so if there are such "residents", plants are best planted in pots. They don’t eat them, but they can dig them out. In the vicinity of fish, crayfish heraks are indifferent, but if you breed larger individuals with large claws, it is better to keep them in a separate container.
Unusual types of crayfish
Although arthropods are generally similar in appearance in many ways, their ability to adapt and survive is dramatically different. For example, river marble crayfish reproduce asexually, and a similar phenomenon in nature is called parthenogenesis.
Females of this type of crayfish can clone themselves without involving males in the process. A similar phenomenon could previously be observed only in higher crustaceans, but never in small river individuals, which reached a maximum length of 8 cm.
Aquarium Crayfish
For freshwater aquarium types of crayfish to take root, it is necessary to constantly maintain cleanliness in water that is well enriched with oxygen.
When choosing a container for such "residents", one should proceed from the parameters that 15 liters of water will be required per 1 individual 6-7 cm. To make pets feel at home, the bottom should be properly formed. It will require snags, gravel or sand, ceramic or metal cylinders, where the crayfish can hide during the day.
Planting plants in a tank depends on the type of cancer, as well as whether the fish will be together with it. Otherwise, the content of these individuals does not cause trouble, the main thing is to remember to close the aquarium with a lid, otherwise you can find your pet on the bed.
