Type — Arthropoda.
Subtype — Crustacea.
Class — Malacostraca.
Order — Decapoda.
Superfamily — Astacoidea.
Family — Cambaridae.
Genus Procambarus — Procambarus.
— Procambarus clarkii [Girard, 1852] — Red swamp crayfish, American Florida crayfish. “Killer crayfish”, “Red Marlboro lobster”, “Red Swamp crayfish”, “White Spotted lobster”. Inhabit water bodies of the southern part of North America. 10-12 cm, excluding claws. These crayfish are popular in aquariums worldwide due to their magnificent coloration. Unlike European crayfish, which turn red only during cooking, these already have vibrant colors during their lifetime.
The coloration of an adult crayfish is usually reddish-brown with bright red spots on the claws. The coloration of crayfish varies slightly depending on keeping conditions, and most importantly, on the diet (ranging from bluish-purple to dark brown). Thus, when using feeds rich in carotenoids, red colors predominate in the coloration of Florida crayfish. With a deficiency of red pigment sources in the menu, the coloration of the decapod shifts towards brown tones, and when fed, say, mussels, light blue or even blue shades predominate in the crayfish’s attire.
There are no Florida crayfish entirely colored in red. As a rule, this color extends only to their claws and a part of the legs. However, in individuals fed on mussels, blue prevails in almost all areas.
The cephalothorax in crayfish is dark. Whitish spicules are scattered over the body and claws of red-colored individuals; in blue-colored ones, they are yellow. By the way, the coloration of crayfish changes precisely during molting. Sometimes a lack or accumulation of nutrients produces an unusual effect. Thus, a bright blue Florida crayfish, after molting, becomes greenish-brown. Or, conversely, a grayish-brown individual begins to shine in a new attire of red colors. Young orange P. clarkii resemble Cambarellus patzcuarensis “Orange” (CPO), but they can be most easily distinguished by the color of their eyes. Young American swamp crayfish have completely black eyes, while C. patzcuarensis has bright eyes.
Thus, you can predetermine the future coloration of your pets and get individuals of the same species colored in different colors. To do this, some crayfish should be fed only pieces of shrimp or carrot, others – chopped mussels and scallops, and still others – lean fish or squid. Or you can get your pets used to dry foods with red color enhancers, and then they will all be colored in one very attractive range.
Practically omnivorous: they pounce with equal enthusiasm on pieces of shrimp or carrots, do not refuse lean fish, meat, heart, squid, lettuce leaves, and actively react to traditional live aquarium foods – bloodworms, corethra, and tubifex. The appetite of decapods is excellent, and the main thing here is not to overdo it. As soon as you notice that the pets are no longer pouncing on food with such greed, it is better to remove food leftovers from the aquarium.
Crayfish are cunning and nimble: if they get a large piece that cannot be swallowed immediately, they try to drag the prey into a shelter for a rainy day. These accumulations cause rapid water spoilage, and in a rotten, stale environment, a crayfish will not last long. Watching crayfish feed is a pure pleasure. At this time, they are most active. When distributing rations among individuals (mainly between leading males), clashes and fights arise, sometimes turning into prolonged tournaments.
Having had their fill, crayfish engage in their favorite activity – controlling their chosen territory, vigilantly watching the movement of neighbors, and in case of the slightest manifestation of aggression on their part, instantly assume a threatening posture. The only exception is recently molted individuals: their shell has not yet hardened, and they are unable to withstand the attacks of their protected peers. Therefore, molted crayfish stay in their shelters, and the empty old skin, so to speak, simulates the presence of the owner at home. Crayfish grow in the process of molting.
Their frequency directly depends on age, feeding regimen, water temperature, and its exchange intensity. The more they eat, the faster they grow and the more often they need to change their shell. To stimulate growth, it is recommended to maintain the temperature at 29-30°C. Under these conditions, with abundant but not excessive feeding, young crayfish can molt weekly (and in some cases twice a week) and become adult individuals by six months of age.
During intensive breeding, one must remember that for successful molting and the formation of normal new integuments, crayfish need mineral substances, including calcium. In order not to tempt fate and not rely on the fact that crayfish will extract calcium from food or water (by the way, in hard water this is quite possible), you should give your pets special mineral supplements, the most affordable of which is “bird” chalk stone.
But there is one nuance here. Soft chalk stone dissolves quickly in water, so it must be given in small portions and consumption must be monitored. With a lack of mineral substances, crayfish may experience a disruption in the molting process and, consequently, the death of the animal. The skin left behind by the crayfish is sometimes eaten, but if it remains unclaimed, it must be removed.
Since this species is herbivorous, an aquarium with live plants will suffer greatly. A separate aquarium with driftwood, rock shelters, and artificial plants is needed. Crayfish need shelters. When keeping several individuals together, the lack of a sufficient number of shelters will lead to conflicts. Often, a wildlife enthusiast wants to keep crayfish in an aquarium with fish. We can say that under certain conditions this is possible. Well-fed crayfish do not catch active and non-bottom fish, and large individuals do not attract their attention either. A hungry crayfish is also a poor neighbor for small and medium-sized fish.
It is better not to plant live plants in an aquarium with crayfish to avoid damage. Aeration is necessary in the aquarium. Crabs use the vertical space of the aqua-terrarium. For crayfish, it is necessary to organize access to the water surface, i.e., make sure they can climb up some objects (tall plants, aquarium equipment hoses, pieces of tufa or driftwood, etc.) to the surface – crayfish can sometimes stay near the surface for a considerable time. However, the aquarium must be covered with a lid and there should be no large holes in it, as they can crawl out.
Crayfish need shelters. When keeping several individuals together, the lack of a sufficient number of shelters will lead to conflicts. Crayfish dig a lot, so you need to ensure secure fastening of heavy decorations. For adult crayfish, shelters can be ceramic tubes, coconut shells, flower pots, etc. Young crayfish hide in thickets of fine-leaved aquarium plants. Red Procambarus clarkii crayfish can be kept in a community aquarium under certain conditions.
These crayfish (at least those receiving normal nutrition) do not touch aquarium fish swimming in the water column. Only small, slow-moving bottom fish and loricariids with long tails (Sturisoma, Loricaria) can constitute a certain risk group. Medium-sized bottom catfish (e.g., Synodontis) coexist peacefully with crayfish. If there are fish that like shelters, to avoid conflicts, there must be enough for everyone.
It should also be taken into account that crayfish are quite timid, and fish move faster than them and can eat all the food dropped into the aquarium before the crayfish reach it, so it is better to make sure the crayfish get food and, if necessary, place it directly into the shelter where the crayfish is. They should not be combined with European or Australian species, as the risk of crayfish plague disease increases.
In order for crayfish to settle in a home water body more easily, it is better to purchase young individuals (6-10 small crayfish) and place them in a 150-200 liter aquarium. Design options can be diverse – from a rocky-driftwood style to a “pseudo-sea”. Optimal keeping conditions for Florida crayfish are: water hardness 10-15°; pH 6.5-7.5; T 20-28°C, aeration, filtration, weekly water replacement up to 25% of the volume. Crayfish breathe with gills like fish, i.e., they use oxygen dissolved in water for breathing, so aeration is necessary in the aquarium. However, crayfish can stay out of water for some time.
Identification: Florida swamp crayfish — Procambarus clarkii.
It should be noted that these animals are very plastic. They feel quite well both in water turned dark brown by mangrove driftwood and in a “pseudo-sea” aquarium oversaturated with various corals and substrate in the form of coral chips. At temperatures of 23°C and below, the growth of crayfish slows down. An individual grown under such conditions can look like a juvenile even at one year of age. But the inhibiting technique is rarely used, because young grayish crayfish look rather nondescript, so for an aquarist, the desire to grow a crayfish faster is still a priority.
At normal growth rates, crayfish mature by one year. By this time, a community with leading males and subordinate individuals is already formed from young crayfish. Their own hierarchy is also established among females. Aggressive towards fish, other crayfish (even of their own species). Even the female must be immediately removed after mating. Relationships in the group are built throughout the life of the crayfish, as individual specimens can lay claim to higher hierarchical places due to any changes. For example, when the leader’s growth slows down or one or both claws are lost during molting.
Dominant individuals try to occupy the most attractive places (usually some elevations). Sitting on their “throne”, the leader controls the situation around and can also get to the provided food faster. When warding off an invading stranger, crayfish not only take threatening poses, spreading their claws to the sides, but also click them against the bottom of the aquarium or stones. Apparently, the more massive the claws and, consequently, their owner, the louder the warning sound. The crayfish does not sit in shelters, but leads a rather active lifestyle.
Males are larger than females, their claws are more voluminous and longer, the front legs of the abdomen are formed into a special copulatory organ and bent towards the cephalothorax, which is wider than the abdomen. In females, the front abdominal legs are either of normal shape or reduced. In the presence of females ready for spawning, crayfish mate all year round. Sensing a suitable individual, males in the aquarium transform. They actively move their claws and whiskers, intensely demonstrating their power. Moreover, neither the size nor the hierarchical position of the individual is of decisive importance during this period.
The agility of the male is considered a priority, and in a sense, his luck. The male’s task is to grab the female with his claws and turn her on her back. The one who succeeds tightly holds the partner in his arms and fertilizes her, after which the pair briskly runs off in different ways. During mating, the male behaves very roughly, often the female loses one or more limbs because the male holds her with his claws. After mating, the female avoids males.
After some time, the female lays clusters of brownish eggs on her pleopods. The time between fertilization and egg-laying is about 20 days. It has been noticed that the next molt after mating becomes the harbinger of spawning, and 2-3 days later the molted female is already carrying the egg cluster. The eggs develop under the female’s abdomen among the swimming legs, with which she constantly mixes them for ventilation. At this time, it is highly advisable to separate the female from the rest of the crayfish and aggressive fish.
An excellent shelter for females is a coconut shell. As a rule, a female with eggs tries to hide in a secluded cave and, putting her claws forward, protects herself and her offspring from the encroachments of curious neighbors. During this period, the female does not have the opportunity to actively look for food, so you need to throw food directly into the shelter where she is located. The incubation period lasts about a month and depends on water temperature. At 28-30°C, development is faster, in a cooler environment – slower.
Newborn crayfish begin to feed on various planktonic organisms, small bloodworms, and tubifex. The size of newborn crayfish is about 7-9 mm. Flaked dry foods can be used as a reserve. In a community aquarium, it is quite problematic for baby crayfish to survive, although with narrow-slit shelters and an adequate food base, there are exceptions. Procambarus clarkii crayfish rarely live more than 3 years.
Identification: Red American crayfish — Procambarus clarkii.
Procambarus (Austrocambarus) cubensis, Blue Cuban crayfish.
Orconectes punctimanus, quadruncus, williamsi. 
