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
|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)|
|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)
|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:
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.
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?”).
- 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.
- What Do Crayfish Eat?
- How to Blanch Cucumbers and Zucchini for Shrimp, Snails, and Fish the Right Way
Keeping and Housing Procambarus Alleni
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.
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.
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.
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.
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)
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.
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.
- 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.
- 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.
- 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.
- Hobbs, H. H., Jr. 1989. An illustrated checklist of the American crayfishes (Decapoda: Astacidae, Cambaridae, and Parastacidae). Smithsonian Contributions to Zoology480: 1- 236.
- 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
- The global trade in crayfish as pets. December 2015. DOI: 10.18353/crustacea.44.0_75
- 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/
25 thoughts on “Blue Crayfish – Detailed Guide: Care, Diet, and Breeding”
This is a very important article and thank you very much for sharing your knowledge with others. And also I need to clarify if I breed blue cray fish commercially what is the density to for parents and babies in a tank
Hi Kasun Wickramarathna,
Sorry, but I do not know the answer.
Personally, I have never kept that many blue crayfish to figure out the safe density when we are talking about a big colony.
I have a 37 gallon tank with about 30 babies blues with mom and dad. Babies are getting big, some babies are an inch in size already. Just noticed mom has black eggs again and it’s only been a month.
Hi Brooke Cusick,
What is your setup? How many hiding places do you have?
Thank you for sharing your experience with us!
Hello i have a female that is berried right now and no male will the eggs just go bad ?
Hi Richard Huisman,
Yes, this is exactly what will happen. The eggs will not be fertilized and the female will drop them. Sorry.
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Hi Dewitt Dittrich,
Thank you for the kind words!
Im thankful for the blog post.Really thank you! Want more.
I’ve been trying to find out why my Alleni seems to be struggling to molt? Last molt was some 3+ months ago and he is very sluggish most of the time with bursts of super-charged activity in between. The water parameters seem normal, perhaps the temperature is too high…±27°C. I have moved him to a 340lt tank with his usual “friends”…funny thing is he has never eaten or attacked any other fish, in fact the Pleco’s and him share caves and hollows. I also have a pair of German Blue Rams that share a hollow from time to time. I’m just concerned that he doesn’t eat now and is “hibernating” under a half coconut shell (which he shares with the male Pleco)!
This is my second blue lobster crayfish
Who is not eating. I have tried 5 different type food. Blood wirms. Veggies. Plants not eating have had her 3 werks i say her cause she has eggs attached recently they are a dark color. Has not moulted either
If she carries the eggs, she should not molt.
What are your water parameters?
What is her behavior?
Have you added anything new in the tank?
Do you have any recomondation as food, how many gram pr day pr gram crayfish?
Hi Henning Stange,
I’ll repeat my answer from another article.
“Well, in home conditions, the optimal dose is usually determined empirically. When you target feed, ensure that the pieces of food served are no more than 1/2 of the crayfish carapace. This should be the ideal size for all protein-rich food items you plan to feed the crayfish, whether meat cubes, shrimp, etc”.
For more information, check out “What Do Crayfish Eat?”
Usually I do not learn post on blogs, however I would like to say that this write-up very forced me to check out and do so! Your writing style has been amazed me. Thanks, very nice post.
I have heard alternatively that crayfish can produce eggs at any time of their lives from any mating cycle. I have also seen this. It can be in a week or a year or more. I wouldn’t count on it that a berried female isn’t fertilized.
Crayfish do have the post-mating spermatophore storage.
However, the average duration depends on the species. Some species can store for a few weeks whereas others may do that for 2 months or even more.
Does the female stop eating when she is berried? I have notice my female does not come out and eat when she is full of eggs.
Hi Edward Poier,
Generally, they do not stop eating completely.
However, their behavior changes significantely. Berried females prefer to hide and come out mostly at night time. So, I would still keep giveng her food.
I appreciate your site tremendously and it has helped me as a beginner with our blue crayfish.
She is a classroom pet that is home with me for the summer. She has been doing great, very active, and loves the bubbler in her 20 gallon tank. However, I am concerned about her lack of energy and she has long “strings” of something (poop maybe?) coming from her tail area. I’ve noticed the strings for 2 days now and don’t remember seeing them before. She has been very very inactive for about a week now. I gave her some frozen sardine about 10 days ago. Could this have caused a problem? We have only known about her molting once at 7:30 pm, when we saw the exoskeleton, however, she had already consumed the entire thing by morning. Her eyes were rather cloudy 2-3 days ago, wonder if she molted and is low-key until her shell hardens. She is the only one in the tank, so no predators. She also seems to have whitish areas on her body. Looking at older pictures of her (got her May 5th) it shows some of those white areas but seems to have new ones now. I am just really concerned about her and don’t know if something is wrong that needs to be treated. You are the most knowledgeable person out there and I’m hoping you can shed some light on what is happening.
Thanks so very much,
Thank you for the kind words!
Regarding white spots, how old is your crayfish? They may lose pigmentation because of old agee. It can also be a lack of astaxanthin (the main pigments associated with external color) in its food.
Have a new blue that is curling his tail, standing on head, laying on back- then acts normal-
How often does it happen? Could you provide more details?