Best Blue Crayfish (Procambarus alleni) Guide

blue crayfish

The blue crayfish lives in stagnant water and sluggishly flowing rivers. If the water threatens to dry up, it digs itself into the mud. Most of the specimens have an intense blue color.

Below you will find the best overview of the blue crayfish covering its natural habitat, characteristics, shape, color, feeding and how to successfully breed the species in your aquarium.

Blue Crayfish (Procambarus alleni): Quick Facts

Common name:Blue Crayfish
Scientific name:Procambarus alleni blue
Origin: Cultivated form (parent form North America).
Maximum size:body up to 10 cm (+ scissors).
Water temperature:18-28 ° C
pH value:6.5–8
Reproduction:In fresh water.
Socialization:Possible with fish (depending on the species) and shrimp.
Description:Striking blue cancer (white underside, sometimes beige).
Aquarium size / facility:From 120 liters. Provide sufficient hiding places. Ceramic caves, wood, etc ..
Food: Commercially available food (better special crab food), vegetables, leaves. 
Remarks: It is better not to use plants as they serve as food.
Difficulty:The blue crayfish does not have any special requirements and is therefore ideal for beginners.
Breeding:Procambarus alleni is a very attractive crayfish in the blue cultivated form. 

The breeding of blue crayfish is unproblematic and productive.

You need enough caves and hiding places for the crayfish offsprings, as well as enough space in the aquarium.

Blue Crayfish (Procambarus alleni): Natural Habitat

The Blue crayfish thrives well in is a breeding product, however, the natural form in Florida waters is usually brown, but purple specimens are occasionally caught.

But now there is also a white form. In blue crayfish, the claws are usually much darker than the rest of the body. Because of its unusual coloration for crabs and the easy-to-meet keeping conditions, it can be seen more and more frequently in our aquariums.

The blue crayfish is not a brackish or seawater inhabitant, it only tolerates fresh water.

Blue Crayfish Care Guide

Blue Crayfish (Procambarus alleni): Features, Shape and Color

The Blue crayfish can grow up to 15cm in its home.

In the aquarium it usually stays smaller with lengths of 10 to 12 cm.

The females become sexually mature from a size of 3.5 cm, but must be larger than the male to mate.

In females, one pair of scissors is larger than the other, in males they are usually the same size.

In the male, the claws are relatively long and tapered to a point; in the female they have a rather rounded, squat shape.

However, only the sex organs provide a reliable distinguishing feature. To do this, you have to turn the Blue crayfish on its back and fold back the tail fan. Then you can see the copulation pen, the so-called gonopodium.

The rear pairs of legs are used for swimming, the front legs for running and climbing. With the foremost pair of legs, he can also pick up food particles from the ground and scrape off growth algae from stones.

Blue Crayfish (Procambarus alleni): In the Aquarium

The blue crayfish is quite easy to care for in the aquarium.

But since it is quite rough and as an omnivore it also preys on smaller fish and does not spare invertebrates either, it should be kept in the species tank and not socialized with other crabs, crabs or shrimp.

As a natural predator, it lies in wait and can also grab fish that swim by with its claws at lightning speed.

The blue crayfish forms territories and defends its territory against conspecifics. For a single specimen an aquarium of 60x30x30cm is sufficient

If you are going to breed, you need an aquarium that is 100x100x100cm to accommodate one male and one female.

Since the blue crayfish likes to climb, the aquarium must be well covered and all escape routes must be excluded. Simply add sufficient hiding and retreat options, especially if you keep several specimens in an aquarium.

If you keep several crayfish in an aquarium, each of them needs their own shelter.

In addition to a cave, the blue crayfish needs fine gravel and sand to dig.

Unlike other crayfish that fish in murky waters, it needs clear water. Therefore you have to provide a suitably robust external filter. The average water temperature should be above 20 ° C, otherwise the crayfish will stop eating.

If you want to plant the aquarium, then onlyplant robust, broad-leaved species such as anubias, giant vallisneria or Java fern, which are also recommended for cichlid tanks.

And if the blue crayfish does not eat anything, it has probably withdrawn into its den to prepare to molt. Because in order for it to be able to shed its skin at all, it has to extract nutrients from the chitin shell until it becomes so thin-skinned that it rips open along a line between the breast shield and the abdomen.

The crab pumps water between the shell and the body, causing it to burst. By hitting the tail fin it finally manages to slip out of the shell and strip it off. The so-called butter crab now retreats into its hiding place for a few days until the new shell has completely hardened and offers the necessary protection. Often it eats up its old remains of armor after successfully surviving its moult. In the aquarium, the blue crayfish can reach an age of around 2.5 to 3 years.

Blue Crayfish (Procambarus alleni): Attitude

The Blue crayfish is easy to look after and suitable for beginners. 

Make sure that you pay attention the total water hardness from 6 ° dH. Other water values ​​do not play a major role. 

Of course, regular water changes are necessary, as is usual with any aquarium.

Since Procambarus alleni eats aquatic plants, synthetic plants are ideal for greening.

He needs clay cavities or other hiding places to molt. Blue crayfish are diurnal.

blue crayfish
Blue crayfish

Blue Crayfish (Procambarus alleni):  Socialization in the Aquarium

Large predatory fish are not suitable for socialization. During the molting phase, the body is soft and the cancer cannot fight back.
The Blue crayfish can prey on slow fish. If the aquarium is well structured, dwarf shrimp are suitable roommates.

Blue Crayfish (Procambarus alleni): Feeding

The blue crayfish is (almost) an omnivore and eats plants

In its native habitat, it feeds on aquatic plants, fallen leaves and detritus, as a scavenger, hunts smaller fish and does not stop at smaller conspecifics.

In the aquarium, you should feed the blue crayfish:

  • Tubifex
  • Dry food in the form of food tablets
  • Food pearls
  • Small water snails
  • Dried leaves from the walnut or sea almond tree contain minerals

You can supplement the food with green foods such as

  • Carrots
  • cucumber
  • peas cut into small pieces

This will prevent the crayfish from harming aquarium plants.

Chunks of food floating above the ground are swirled in with the jaw fans and then sucked in by the mouth.

The blue crayfish can see well with its stalk eyes, but when searching for food it relies on its sense of smell and taste.

Young crayfish can also tolerate a higher protein diet, such as normal fish food and food tablets. However, growing too quickly can damage them. The main food here should also be vegetable.

Blue Crayfish (Procambarus alleni): Breeding

Breeding in the aquarium is possible, provided the tank is large enough and the proportions of males and females are correct.

When mating, the male turns the female on its back and holds it with its claws so as not to be injured.

A female can bear between 50 and 300 young.

The eggs hang on the females webbed feet and are moved back and forth during brood care in order to supply the clutch with fresh oxygen.

The gestation period is 1 to 2 months depending on the water temperature.

The female has 5 pairs of webbed feet, while the male only has three.

If the water temperature is increased to 26 to 28 ° C, the young crabs grow up very quickly and after 1 ½ months they already reach 4 cm in length. The blue crayfish are sexually mature after about 4 months.

The offspring of Procambarus alleni is problem-free and productive. 

The mother animal carries the eggs under her abdomen until they are fully developed.

If the young crabs have enough hiding places, there are few losses. 

With good feeding, the animals grow up quickly.

Blue Crayfish hatching

Blue Crayfish (Procambarus alleni): Typical diseases

Even through the crayfish has a hard outer shell, it is still susceptible to fungi and bacteria.

1. Crayfish plague

Crayfish plague is arguably one of the most feared and well-known diseases that can affect crayfish. It is caused by the tubular fungus Aphanomyces astaci.

How do the crayfish get infected?

The infection occurs through zoospores, which can actively move with the help of two flagella. When infected crayfish moult or die.

Rapid growth of the fungus and optimal mobility of the zoospores are around 20 ° C. Below 10 ° C and above 25 ° C, the growth of the fungus shows only limited activity and the disease thus takes longer to break out, which then ends just as fatally. 

What are the symptoms?

Symptoms appear no earlier than one day after infection. 

  • These can be expressed by white spots in the muscles
  • Brown discoloration on the shell
  • The crabs also stay in open water during the day and appear limp. 
  • Symptoms of paralysis, imbalance, loss of limbs, increased scratching of the entire armor can occur or the animals linger on the ground sluggishly and lying on their side, or even mass deaths of entire populations within a short time

Can it be treated?

A treatment is so far unknown. In the event of infection, losses of up to 100% can be expected. 

2. Rust disease, burn spot disease

How do the crayfish get infected?

The crayfish get infected with these two diseases due to fungi (e.g. Ramularia astaci, Cephalosporium leptodactyli, Didymaria cambari), injuries and gram-negative bacteria (Aeromonas, Pseudomonas, Citrobacter etc.).

What are the symptoms?

  • The occurrence of individual small, spots is often due to injuries caused by a fight, in the case of mechanical damage to the armor, as well as to fracture spots when limbs are severed.
  • Fungal spores and bacteria settle there and cause inflammation with darkening of the shell.
  • In the chronic stage, brown or black spots appear
  • As the infection progresses, brown areas get bigger.
  • In the advanced stage, the black-brown spots tend to remain point-like, grow up to 1 mm in size and can spread over the entire shell.

Can it be treated?

  • If only small or superficial areas are affected, these are usually thrown off during a molt.
  • In the advanced stage, use a binding agent to make tap water suitable for shrimp and to bind any heavy metals in the water. Most binding agents contain additional antibacterial agents that kill germs in the water. So that the harmful germs in the water that cause darkening are reduced.

3. Other diseases

There are a number of other bacteria, fungal spores and viruses that can be dangerous to the cancers. A healthy, balanced diet has a preventive effect, with leaves playing an important role in strengthening the immune system.

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