Blue Crayfish – Detailed Guide: Care, Diet, and Breeding

Procambarus alleni are more commonly known as Blue lobsters, Florida crayfish, Electric blue crayfish, Everglades crayfish, Sapphire crayfish, and Blue Crayfish. The variety kept and sold in aquariums is primarily a brilliant blue color, but they can also be white, red, and brown, especially in the wild.

Blue crayfish is a very hardy species. It is very easy to care for them. They are not too fussy about water quality and their diet is an omnivore. So, If you are a beginner and would like to get into breeding crays, this might be a good species to start with. 

Procambarus alleni is a freshwater crayfish that has acquired immense popularity in the aquarium trade and hobby.

Unfortunately, their aggressive behavior, size, and feeding habits make them suitable for a single-species setup. It can be almost impossible to keep Blue crayfish in a community tank. Keep reading for everything you need to know about Procambarus alleni and keeping these fascinating crayfish in your own aquarium.

Quick Notes about Procambarus Alleni 

Name	Blue crayfish
Common Names	Blue lobsters, Florida crayfish, Electric blue crayfish, Everglades crayfish, Sapphire crayfish, etc.
Scientific Name	Procambarus alleni
Tank size (minimum)	20 gallons (~90 liters)
Keeping	Easy
Breeding	Easy
Size	10 – 12 cm (4 – 5 inches)
Optimal Temperature	22 – 27 C (71– 80 F)
Optimal PH	7.0 – 8.0 (6.0 – 9.0)
Optimal GH	6 – 8 (3 – 22)
Optimal KH	4 – 6 (2 – 18)
Optimal TDS	150 – 200 (100 – 1000)
Nitrate	Less than 60 ppm
Diet	Omnivore / Herbivores (as adults) Omnivore / Carnivore (as juveniles)
Temperament	Very aggressive
Life span	up to 5 year
Color Form	Different color variations: reds, oranges, and browns but blue is the main one.

Origins, Natural Habitat of the Procambarus Alleni 

Blue Crayfish come from freshwater marshes, ditches, streams, wetlands, and flood plains that are primarily found in Florida, south of the panhandle. Though they have also been found in California, France, and Germany, these are believed to be colonies introduced from aquariums.

The crayfish live in water that has little to no movement but can survive extended dry periods in these littoral zones by burrowing in sand, mud, or clay to stay hydrated. Some of the waterways that house Blue Crayfish are brackish, with a salinity of up to eighteen (18) parts per thousand. 

Description of the Procambarus Alleni 

Blue Crayfish are average size for crayfish species, growing from 4 – 5 inches (10 – 12 centimeters) in length. However, there are reports that in the wild some individuals can measure up to 18 cm (7 inches).

The general life span for the Procambarus Alleni Blue crayfish is up to 5 years with proper care.

This species can be several color morphs including reds, oranges, and browns, but they are most commonly seen in their bright blue form. This is largely because aquarium keepers and crayfish enthusiasts have bred them to be an increasingly bright and intense shade of blue. They are usually speckled with lighter patches or dots.

Difference Procambarus Alleni and Procambarus Clarkii

It is very easy to confuse Procambarus Alleni and Procambarus clarkii (check out the guide). Basically, these two species are identical in everything but the areola on the back. Areola is a small space between two parts of the carapace. Blue crayfish have two shell plates almost touching at the top of the back. Procambarus clarkii crayfish almost do not have this area. 

The Behavior of the Procambarus Alleni 

Blue crayfish are nocturnal animals and love darkness. They also like to burrow and hide in caves. Procambarus Alleni, like their cousins Procambarus clarkii, are very aggressive and territorial. Although there can be some exceptions to this rule, there are no guarantees of peaceful cohabitation.

Therefore, unless, you are an experienced crayfish aquarist, you should not attempt to house multiple blue crayfish in the same tank. However, if you are still willing to take the risk, you will need to provide a lot of hiding places. I mean a lot – a lot, so the crays can hide from each other.

Tip: If you are planning to keep multiple crayfish in the same tank, introduce them to the tank all at the same time. The reason behind it is that it might reduce the level of initial aggression. Otherwise, the first one is much more likely to view newer ones as invaders and immediately attack.

Procambarus Alleni Molting

Growth in crustaceans is a highly complex and asynchronous process. Their size increases directly following ecdysis (molting or shedding their old exoskeleton). According to some studies, the complete hardening of the exoskeleton takes about 3 days.

The early signs of molting include:

• lack of appetite
• slowdown in activity.

During this period, the crayfish ingests calcium into an internal organ, not into the exoskeleton.
The frequency of molting in Blue crayfish decreases with increasing age. For example:

• Baby blue crayfish molt every few days.
• Juveniles blue crayfish molt in a range of between 1 – 3 weeks.
• Adult crayfish molt in a range of between 4 – 8 weeks.

When Blue Crayfish molt they will consume their entire exoskeleton so as not to lose the nutrition it carried. So, do not feed it for a few days after the molt.

A sufficient hiding place should be ensured so that this can be done privately. They usually want to hide away when they are molting or have recently been molted. During this time, they are extremely susceptible to attacks from other crayfish and even fish.

The crayfish should be provided with plentiful sources of calcium to prevent incomplete molts.

I highly recommend reading my articles:

• How to Supplement Shrimp and Snails with Calcium.
• Crayfish and Molting Process. 

Is Procambarus Alleni Plant Safe?

No, Blue crayfish are not plant safe. It is absolutely not possible to keep this species in a planted tank. For example, Anacharis, Hornwort, and Java Fern (read the guide) are favored by a large number of crayfish species. The only plants that crayfish tend to leave alone are floaters (read my article about Top 7 floating plants for beginners).

Blue crayfish will eat, cut, and uproot everything. Of course, you can also buy some cheap plants and keep replacing them once a month or so. After all, this is their preferred habitat, in the wild. The analysis showed that crayfish densities were consistently higher in marsh habitats dominated by plants

Note: If you need a plant safe crayfish, check out my guide “Dwarf Mexican Crayfish  – Detailed Guide: Care, Diet, and Breeding”.

Identifying and Sexing Procambarus Alleni

Male blue crayfish have much larger claws than females. Their tails are also narrower.

The male crayfish has two L-shaped appendages (sperm transfer organs) behind their legs called claspers. The females have a circular sperm receptacle between the bases of the last two pairs of walking legs. 

Related article:

• How to Tell If a Crayfish is Male or Female

Feeding Procambarus Alleni

Blue Crayfish are omnivorous and opportunistic feeders. They will eat just about anything they can get their claws on. While they will largely feed from the substrate of their tank, they will also eat live plants kept in their tank, dead and dying fish, and snails, in addition to blanched vegetables and sinking pellets and wafers.

They are also cannibalistic and will not hesitate to eat other crayfish in the tank. Especially if they feel there is a threat to their territory or they lack protein in their diet.

So, what can you give them? Suggested foods for your crayfish are:

• Shrimp tails.
• Fish, shrimp, or crab pellets (for example, Hikari products also improve crayfish coloration. You can read my article “How to Enhance Shrimp Color?”).
• Spirulina.
• Dead fish or shrimp.
• Bloodworms, blackworms, etc.
• Vegetables Crayfish love veggies (peas, romaine lettuce, potato, carrot, cucumber, etc)
• Plants (This is also one of the reasons people with planted aquariums tend to avoid crayfish).
• Calcium supplements (Eggshells, cuttlebone, etc).

Blue crayfish should be fed every day to prevent them from attacking their tank mates. Do not overfeed. Remove any uneaten food after 24 hours.

Related articles:

• What Do Crayfish Eat?
• How to Blanch Cucumbers and Zucchini for Shrimp, Snails, and Fish the Right Way

Keeping and Housing Procambarus Alleni

Tank Size:

Those wishing to keep Blue Crayfish should expect to house them in a tank of at least 20 gallons (~90 liters) for one adult.  If more than one crayfish is kept in the same tank they should be the same size and different genders, otherwise, the smaller crayfish will be attacked and, most likely, eaten by the larger crayfish.

Blue Crayfish should be kept in a freshwater tank. However, they can also tolerate a small amount of freshwater salt, it won’t hurt them.

Important: Blue Crayfish are expert climbers and a tight lid is necessary so that they do not escape the tank and become injured. If your crayfish escapes, it will dehydrate and die, in a few hours.

Substrate and Decorations:

Blue Crayfish should be provided with sand or gravel substrate into which they can burrow. Procambarus Alleni can adapt to their environment and change their coloration in a response to their background. They use this survival technique to camouflage against predators. In aquaculture, it would be best that aquarists use a blue substrate to enhance the color.

There should be plenty of dark areas for them to hide in and these should be created out of rocks, driftwood, PVC pipe, artificial plants, etc.

Note: If you are planning to house several crayfish, each of them needs a hiding place to feel secure in different parts of the tank! Keep in mind that they are territorial and do not like neighbors.

It’s unlikely that the crayfish will leave the tank the way that it was initially set up. The Blue Crayfish will rearrange it, digging into the substrate and dragging anything that is light enough for them to move. For this same reason, live plants should only be kept in the tank with Blue Crayfish under the condition that they will be cut and consumed.

Water Parameters:

The Blue Crayfish can withstand a wide variety of pH levels in their tank. However, it is most important that the pH of the water in the tank should be kept stable. As long as the pH does not fluctuate wildly and remains within the range of 7.0 – 8.0, the crayfish should not suffer adverse effects. Keeping pH towards neutral 7 provides the greatest benefit for the crayfish.

Note: Crayfish should not be in the water with a PH of less than 7. Although they can tolerate even low pH (6.0 – 6.5) for some time. It might cause problems with the molting eventually.

Nitrite, nitrate, and ammonia levels should be at or approaching zero after the nitrogen cycle has been established. Do not add them in an uncycled tank!

The ideal carbonate hardness (KH) of the tank water should be between 4 – 6 and the general hardness should be between 6 – 8. However, do not worry, if you cannot hit these numbers precisely. Procambarus alleni are very hardy species and can live in a wide range of water parameters.

Before the crayfish are added, the water in the tank should be free from chlorine and any other harsh chemicals that can be found in most residential tap water. Distilled water can be used, or a chemical water conditioner can be added to eliminate these contaminants.

Temperature

Stability is important when considering the temperature of the Blue Crayfish tank. The range of acceptable temperatures is anywhere between 68 – 75 °F (18 – 24 °C). If a heater is required, it must be kept out of the reach of the Blue Crayfish or else risk being moved or damaged by their claws.

Filtration

The filter will serve to keep the tank clean as well as oxygenate the water, which is extremely beneficial to the Blue Crayfish.

The filter should have a sponge cover and be kept out of reach of the crayfish. This is especially true if a male crayfish and female crayfish are kept in the same tank. Keeping the filter out of reach will protect against any babies being sucked into the filter in the case of breeding.

Tip: I would not recommend sponge filters with Procambarus alleni. Their claws will damage and tear apart the sponge.

Bubbler

Surprisingly, but Blue crayfish can drown if they are kept in water without supplemental oxygenation. This makes air bubblers mandatory. Instead of the bubbler, you can put a rock in your tank so that the crayfish can climb out of the water if desired. This will prevent them from drowning.

Regardless of their hardiness, it will be better to acclimate them (read more about it).  

Tank Equipment (links to check the price on Amazon) Filter: Marineland Penguin Power, Sponge filter. Aquarium pump: Air pump Bubbler: Hygger Aquarium Air Stone Kit Inert Substrate: Carib sea sand, Play sand, etc. Decor: Malaysian Driftwood, PVC pipes, Coconuts, Decorations, etc.

Mating Procambarus Alleni

Blue crayfish become mature when they are about 4 – 5 cm (~1 inch). If a female is interested in mating, she will allow a male to approach. After that, the male clamps her claws and puts her on the back. Mating can last from several minutes to an hour or so.

Note: When they are done, they can become aggressive to each other. So be ready to intervene. 

Breeding Procambarus Alleni

In order for Blue Crayfish to mate, there must be ample room in the tank. However, because of the cannibalistic habits, I would strongly recommend a separate setup.

Once the female crayfish has berried – the term for when she is carrying her eggs under her tail – she should be removed to a separate tank of at least 10 gallons. Reproductive output in this species increased linearly with female size (from 50 to several hundred eggs), and fecundity scaled linearly with habitat conditions.

Depending on the temperature, the eggs will hatch in 20 – 30 days. When the baby blue crayfish emerge, they ride on the mom’s back and under her tail for a couple of days. In some cases, it can be even a week or two. After that, they will start detaching from the mother and crawl away.

This is a very important time. There are pheromones that the female crayfish secretes which are called maternal pheromones. They encourage the young to stay close and the female to protect those their babies.

Once, these pheromones wear off, it is to their advantage to be as far away from their mother as possible. Otherwise, there is a great risk of her eating the babies.

That is why, after the eggs detach from the female crayfish, she should be removed back to the original tank.

As the babies get larger they will need to be removed to larger tanks to avoid more cannibalization, but with plenty of space and food and dark places to hide, these babies will grow into adult Blue crayfish.

Interesting fact: In the wild, the life cycle of Procambarus alleni is timed to coincide with the flood-dry seasonality. The young of the year hatch in burrows near the end of the dry season, where they remain with adult females until the next flood. At the start of the flood season, the young juveniles disperse. Young adults may move up to 1 km during the flood season to colonize flooded marshes and exploit new resources.

If you get interested and want to know more, read my article “Introduction to the Crayfish Care – Setup, Diet, and Facts”.

Procambarus Alleni and Suitable Tankmates

A delicate balance must be struck for fish to live in a tank with Blue Crayfish. Cichlids are too large and aggressive and will attack the crayfish, but Red Tail Sharks seem to be fast enough to avoid their claws. However, they require very large tanks to thrive.

Other fish that might work well in Blue Crayfish tanks are: Tiger Barbs, Zebra Danio, Rainbow Darters, Tetras, and the like.

Any fish that swim near the bottom of the tank is not going to fare well in a Blue Crayfish tank as they will likely run into the claws of the crayfish. The same is true of slow-swimming fish.

Note: Nonetheless, though it is possible for crayfish to coexist with fish I would not recommend it.

Read my article “Can You Keep Crayfish With Other Fish?”.

Snails, Shrimp, and Procambarus Alleni

Be aware that Blue crayfish are scavengers as well as hunters. They will grab anything passing, swimming or crawling by. Therefore, shails and shrimp can easily become crayfish food. Although dwarf shrimp are very fast for the blue crayfish. You will still lose shrimp from time to time.

In Conclusion

Blue crayfish are much more enjoyable to watch and much more active than most fish. All of them have unique personalities.

They are very resilient which makes them a great choice for beginner aquarists. Unfortunately, they are too aggressive and destructive to keep them in a community or planted tank.

Related articles:

• Introduction to the Crayfish Care – Setup, Diet, and Facts
• How to Set Up a Crayfish Tank
  

References:

1. Jordan, F., C.J. De Leon, and A.C. McCreary. 1996. Predation, habitat complexity, and distribution of the crayfish Procambarus alleniwithin a wetland habitat mosaic. Wetlands 16(4):452-457.
2. Dorn, N.J., and J.C. Volin. 2009. Resistance of crayfish (Procambarus spp.) populations to wetland drying depends on species and substrate. Journal of the North American Benthological Society 28(4):766-777.
3. Acosta, C.A and Perry, S.A. 2000. Differential growth of crayfish Procambarus alleniin relation to hydrological conditions in marl prairie wetlands of Everglades National Park, USA. Aquatic Ecology 34: 389-395.
4. Hobbs, H. H., Jr. 1989. An illustrated checklist of the American crayfishes (Decapoda: Astacidae, Cambaridae, and Parastacidae). Smithsonian Contributions to Zoology480: 1- 236.
5. Taylor, C.A., Schuster, G.A., Cooper, J.E., DiStefano, R.J., Eversole, A.G., Hobbs III, H.H., Robison, H.W., Skelton, C.W. and Thoma, R.F. 2007. A Reassessment of the Conservation Status of Crayfishes of the United States and Canada after 10+ Years of Increased Awareness. Fisheries, American Fisheries Society32(8): 372-389
6. The global trade in crayfish as pets. December 2015. DOI: 10.18353/crustacea.44.0_75
7. Introduction The blue morphed Procambarus alleni is one of the most common invertebrates for trade within the United States aquaculture. https://slideplayer.com/slide/10774224/