Procambarus clarkii – Detailed Guide: Care, Diet, and Breeding

Procarambus Clarkii red

In this guide, I have done extensive research on Procarambus Clarkii, commonly known as Red swamp crayfish, Louisiana red swamp, Red crayfish or Mudbug, to describe care, diet, and breeding in all possible details. As always on my blog, you will find here not a vague description but facts.

Procarambus Clarkii can live in almost any freshwater aquarium and are among the toughest freshwater tank inhabitants available to the hobby. This is a highly adaptable species. Its ability to grow and mature rapidly made it the dominant freshwater crayfish in the world. The only problem is that it is not suitable for planted or community tanks.

Red swamp crayfish are also highly resistant to environmental stress, including extreme temperatures, the absence of water, high salinity, and the presence of pollutants. All these qualities make it an excellent choice for beginner aquarists.

NEVER release Procarambus Clarkii into the wild. Check your state laws before purchasing. This is a restricted (banned) species in some US states and European countries due to their potential to become invasive. For example, this species is listed among the 100 worst invasive species in Europe, under the EU Regulation 1143/2014 regarding alien invasive species.

Quick Notes about Procambarus clarkii

Name Red swamp crayfish
Common Names Red crayfish, Mudbug
Color variations – Neon red crayfish, Scarlet crayfish, Ghost crayfish, White specter crayfish, etc.
Scientific Name Procambarus clarkii
Tank size (minimal) 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 3 year
Color Form Different color variations: orange, reddish-dark, blue, yellow, white, black but red is the main one.

Natural Habitat of the Procambarus clarkii

It is native to parts of Mexico and the United States and has established in all continents except Antarctica and Oceania.

Red swamp crayfish live in a variety of freshwater habitats.  In the wild, they can be found in standing freshwater such as lakes, ponds, canals, irrigation ditches, rice fields, marshes, and swamps.

Description of the Procambarus clarkii

Procarambus Clarkii color variationsIn general, this species has a dark red body (carapace). However, in the aquarium trade, it is possible to find different color variations such as:

  • Orange (Neon red crayfish)
  • Reddish dark (Scarlet crayfish)
  • Blue (Ghost crayfish)
  • Yellow (Orange ghost or Fireball crayfish)
  • White (White specter crayfish)
  • Black varieties

One of the unique things about them is that they have a hook on the claws. In addition, unlike other crayfish species, Procarambus Clarkii does not have areola on the back.

Procambarus_virginalis and Procarambus Clarkii differenceJuveniles are usually light green with a narrow dark band on either side of the abdomen and a broader lighter band along the dorsal surface.

Fully grown Procarambus Clarkii can reach 3.5 – 12 cm (2.2 to 4.7 inches) in length. There are reports that in the wild some individuals can measure up to 15 cm (6 inches).

Life span does not exceed 3 years but can reach 5 years in higher latitudes.

The Behavior of the Procambarus clarkii

Procarambus Clarkii can make great aquarium pets if you understand their natural tendencies and behaviors and care for them accordingly.

This species is defined as nocturnal. Although some individuals do not mind be active even in the day time.

They have 2 movement patterns, with one or more short peaks of intense locomotion (“wandering” phases) alternated with periods of scarce mobility, with slow speeds or no movement (“stationary” phases).

They are very aggressive and tend to fight almost all the time. Procarambus Clarkii is a solitary and territorial creature. They will pinch and claw when they feel threatened.

So a large tank will be crucial in the attempt to keep multiple crayfish together in the same environment.

It is possible to hold your crayfish on a flat palm when they are calm, but keep in mind that they are able to defend themselves.

Tip: If you are new to handling crayfish or have children handling the animals, you may want to consider scooping your little friend up into a plastic cup when handling must occur.

Like many crayfish species, Procarambus Clarkii is an efficient digger. In the absence of shelter, both males and females began burrowing rapidly. In the wild, burrows are used as a refuge to avoid predation, dehydration and environmental stress as well as to nest.

According to observations, the average length of the excavated tunnels ranges from 20 – 80 cm (8 – 30 inches).

Interesting fact: Despite the great importance of these shelters, they seem not to return to previously occupied burrows at the end of their foraging excursions despite the time and energy expended to excavate them.

Procambarus clarkii Molting

Crayfish must molt or shed its hard exoskeleton to increase in size. Molting interval and growth rate is affected by a number of variables, including water temperature, population density, water quality, and food quality and quantity.

Depending on the age and water temperature, molt intervals for crayfish range from 4 to 30 days.  For example, baby crayfish molt every few days, while juvenile crayfish may molt every 7 – 10 days.

Interesting facts: The molting process is controlled by environmental and endocrine hormones, which are located in their eyestalks.

Like all crustaceans, Procarambus Clarkii becomes very lethargic for a few days beforehand and does not eat as much. The cloudy eyes are a sign that it is going to molt.

After molting, the metabolic demand (to harden the shell) for calcium is particularly great. Crayfish use calcium to produce a new and healthy shell.  I highly recommend reading my article “How to Supplement Shrimp and Snails with Calcium”. These nutrients are necessary in abundance especially following the molting of your crayfish.

Sexing Procambarus clarkii

Sexually mature Procarambus Clarkii exhibit distinct characteristics, including darker coloration, enlarged claws, and hardened sexual structures. Mature males develop prominent hooks (the genital pores) at the base of the third and fourth pair of periopods (walking legs). Whereas in females the first pair of abdominal appendages have no modification.

Are the Procambarus clarkii Plant Safe?

Unfortunately, Procarambus clarkii species is not plant safe. It is absolutely not possible to keep them in planted aquariums. They will eat, cut and uproot everything that is possible. They are lawnmowers.

Procambarus clarkii is an opportunistic omnivore with a primarily plant-based diet. The results of the study showed that adult crayfish consume relatively larger biomass of fresh plants and do not exhibit a preference for any animal and preferred plants over meat (earthworms).

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

If you add vegetables to their diet, it really helps. It tends to distract them from the plants for some time.

Feeding Procambarus clarkii

Procambarus clarkii is a generalist omnivore species, they are natures natural scavengers.  As a nocturnal animal, they most actively seek nourishment in the early morning and just before dark.

In their natural habitat, crayfish feed on plant, algae, animal detritus, macrophytes, dead and live animals such as molluscs, insects, annelids, nematodes, platyhelminthes, tadpoles, fingerlings, fish, snails, etc.

Surprisingly, crayfish do not exhibit a preference for any animal prey. According to multiple studies, pre-adults and adults tended to be more herbivorous, whereas juveniles tended to be more predatory. Juveniles cannot be classified as true detritivores or herbivores since they rely on animal prey for their rapid growth. For example,

Juvenile Procambarus clarkii Adult Procambarus clarkii
Animal matter 44% 20%
Detritus 29% 41%
Plants 27% 39%

However, when food resources are limited for crayfish, they lose much of their selectivity and will consume almost all plant or animal food items.

Diet

It is important that you ensure that the diet of your pet crayfish is rich in nutrients, especially calcium and iodine. Use these results to optimize the diet of the Procambarus clarkii in the tank.

If you are unsure of the nutrient makeup of the food that you are feeding your crayfish, supplement their diet with store-bought crustaceans feed pellets. These pellets are specially formulated to contain the full spectrum of nutrients for your pet crayfish.

If you want to be sure that the newest additions to your family are getting plenty of nutrition, boiled lettuce, cabbage, zucchini, carrots, etc. is a popular choice for feeding your new little friends.

You can read my article “How to Blanch Cucumbers and Zucchini for Shrimp, Snails, and Fish the Right Way.”

It is best to feed your pet crayfish in the early morning or at dusk when it is likely to be most active.

Tip: Once your crayfish has had a few hours of food present at its peak feeding time, remove any unused food to avoid the growth of unwanted bacteria in the tank.

Tip #2: Color enhancing food such as Hikari Shrimp CuisineHikari Micro Wafers, and Hikari Tropical Crab Cuisine (link to check the price on Amazon) can be a good option to go for if you want to maintain or improve that coloration of your crayfish.

You can read my article “How to Enhance Shrimp Color?”

Keeping Procambarus clarkii

Procambarus clarkii is extremely tolerant of poor water quality. However, if you do not want to test their limits, the ideal water parameters will be: pH 7 – 8, temperature 22 – 27, GH 6 – 8, KH 4 – 6. Make sure to test your water frequently to ensure the water is hard and the pH is on the alkaline side. Otherwise, your crayfish can have trouble molting.

Although Procambarus clarkii can tolerant, and reproduce in a wide range of aquatic environments. Caring for your pet crayfish still requires some specific knowledge and skills.  For example:

Tank Size

It is recommended that you provide a tank that is at least 20 gallons per adult crayfish you plan to house in the tank. However, even with ample space, there is no guarantee that the crayfish will not act in a territorial manner attacking and even eating their tank mates. Actually, Procambarus clarkii will be perfectly happy to be the only pet in the tank.

Important:  Crayfish are excellent escape artists. Therefore, you need to hide or protect all cables in any tank.

Substrate

Remember that Procambarus clarkii will dig a lot. That is why a few inches of aquarium soil, sand or fine gravel will be the best choice.

This will help your crayfish to feel safe and stress-free. Keep in mind that aquascaping does not work with crayfish. They will push, drag, dig and rearrange everything in your tank.

Plants

Floaters, cheap and fast-growing live plants are a great choice for crayfish tanks as they can serve as natural food for your crayfish. Live plants will also help to keep the tank clean, serve as a source of food for your crayfish, as well as providing safety and protection for your crayfish, which can reduce territorial and aggressive behavior.

Choosing artificial plants is a more low maintenance option that is perfectly fine.  Artificial plants will still provide beautiful and functional hiding places for your little crayfish to feel safe and secure.

Decorations and Hiding Places

Provide them with lots of places to hide or they burrow and dig even more often than usual. They just want places to hide out! Crayfish naturally like to have some shelter and safety be it from rocks, driftwood or plants.

Filtration

When it comes to shrimp, snails, and small crabs, I usually recommend having sponge filters. They are cheap and provide everything that these animals need. However, having sponge filters with these crayfish is just a very bad idea. The point is that they like to chip and chew on it. With time, Procambarus clarkii will simply tear and break apart the sponge.

Do not put it in an uncycled tank. Although they are pretty hardy and potentially can survive even during cycling, you do not want to take your chances.

Bubbler

If the aquascape in your tank does not allow your crayfish to get to the surface, definitely add a bubbler. The bubbler is essential as they need oxygenated water.

Note: Although Procambarus clarkii can live in swamps, they cannot swim far up for oxygen. So they crawl out to the land from time to time.

Tank Equipment (links to check the price on Amazon)

Interesting facts about Procambarus clarkii tolerance:

  • Adult Red swamp crayfish can live in salinity <15%. Tolerance to salinity is directly proportional to crayfish size. Newly hatched young die at 15 parts per thousand (ppt), and juveniles die at 30 ppt after one week.
  • Temperature range of 8 – 33 C (46 – 91 F).
  • Although this crayfish is an aquatic species, it is highly resistant to air exposure and is able to survive for several days outside the water (under humid conditions).
  • They can ingest and eventually store in its tissues large amounts of heavy metals.
  • They are very tolerant of copper! Procambarus clarkii has physiological mechanisms to regulate the levels of copper, which enable them to successfully cope with exposure to higher levels of copper in their environment without exhibiting tissue bioaccumulation.

When you get your crayfish, it should come in a plastic bag or container of water. Do not put your crayfish directly in the tank!  You can shock the system of your crayfish by changing water temperature too quickly.

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

Mating Procambarus clarkii

Procarambus Clarkii matingSometimes it may be difficult to determine if your crayfish are mating, or simply fighting. When the male approaches the female, she will usually react aggressively at first.

After sex recognition, male courts female through a specific sequence of movements followed by copulation. The male flip over the female and deposits the spermatophore in a protective receptacle in the female.

According to the studies, the role of the female is not always passive. If a female is in a high sexual state and a male is non-active, on a few occasions the females can attempt to move even underneath the males.

Mating between male and female Procambarus clarkii usually occurs in open water before females start to burrow.

According to observations, the smallest ovigerous female captured was 39.50 mm (1.6 inches). Males usually reach maturity at 25 – 40 mm (1 – 1.6 inches) in length.

Interesting fact: Strength does not play any role in mating. Even when the female is bigger and stronger than the male, she will let him “defeat” her and flip over. The results of the study show that, if the females are not ready to mate, they will always escape even when the males are bigger and stronger.

Breeding Procambarus clarkii

Depending on environmental conditions, (after mating) the female safeguards herself in a burrow and starts oviposition. In the wild, this process may occur in open water but this is very uncommon.

The number of eggs varies with female size and water temperature. A 10 cm female may produce up to 500 – 900 eggs, while smaller females may produce around 100 – 200 eggs. At the same time, under low temperatures (13C) even large females can produce only 30 – 40 eggs (ten times less!).

Eggs have 6 stages of development.  Egg diameter increases from 0.3 mm in stage 2 to up to 1.6 mm in stage 6. Developing eggs increase in size, and change from a light color to dark as they mature.

Once laid, eggs hatch in as little as 3 weeks at 21 to 24 C (70 to 75 F) and 4 to 5 months at 12 to 15.6 C (53 – 60 F). Growth inhibition occurs at temperatures below 12 C.

Interesting fact: Procambarus clarkii can reproduce in slightly brackish water (at 5 gL–1 salinity).

Rearing baby Procambarus clarkii

You should separate the gravid female from other crayfish, the sooner the better. Obviously, you will need a second tank for that. There is no need for the big one because at that stage females do not move much and tend to hide in their shelter (or burrow) all the time.

Newly hatched crayfish are attached to pleopods (swimmerets) on the female’s abdomen through several molts or about 30 – 35 days. Hatchlings remain with the female for several weeks after their second molt although they are no longer attached to swimmerets.

Once the babies leave the mother’s tail, put her back into the main tank and leave the young in the new tank. It will help you to prevent any aggression from her side.

Their complete separation from the mother will be followed by 2 to 3 weeks of voracious eating. At this stage, they require a lot of protein and in the absence of food can start cannibalizing fast. Therefore, incorporate a lot of hides with rocks and loose debris for the babies to hide from each other.

Under ideal conditions of 22 to 30°C (75 to 86°F), crayfish can mature in 3 months. A minimum of 11 molts are necessary for hatchlings to grow to sexual maturity.

Procambarus clarkii and Suitable Tankmates

Though it is possible for crayfish to coexist with other crayfish and fish, it is not recommended.  Read my article “Can You Keep Crayfish With Other Fish?”.

Like many crayfish species, Red swamp crayfish are naturally solitary and territorial creatures. They will most often lash out at any other creature that they perceive to be invading their home.

The good news is that you don’t need to worry about your crayfish becoming lonely without the purchase of other pets. Your crayfish will live it’s best life when kept in a safe and solitary habitat.

Fish and Procambarus clarkii

It is not recommended that you house crayfish and other pet fish in the same tank.  Though crayfish are ultimately scavengers, they are omnivores and opportunistic eaters. Which means that they can and will eat fish when given the chance.

They generally will not kill a fish in one blow, but will slowly wear the fish down over a period of time through smaller attacks. Over time, the fish will become weakened due to injuries and stress.

When the fish is in a much weakened state, the crayfish will prey on the fish for food.  You can add small feeder fish to the tank when the intention is for them to serve as food for your crayfish.

In addition, Procambarus clarkii preys on fish eggs.

Tip: If you do add fish, I would not get too attached to it. Feed your crayfish daily to reduce the chances of snatching a fish up.

 Snails and Procambarus clarkii

They are active predators of snails. For example, in Africa, Procambarus clarkii has been introduced as a biological control agent to reduce snail populations, which are intermediate hosts of schistosomiasis.

Big snails potentially have a chance to survive long enough. However, in general, I do not see how it is possible to keep them in an aquarium with snails successfully. Crayfish can eat small snails with its shell.

Shrimp and Procambarus clarkii

If you are a shrimp breeder, NEVER keep them with shrimp. You will lose shrimp, this is a fact.

Conclusion

Red swamp crayfish (Procambarus clarkii) are a great, low maintenance and easy to breed pet as long as you are providing the correct habitat for them to remain healthy and happy.

This is a very resilient species. So, if you are new to aquarium hobby and make a lot of mistakes do not worry, they can adapt to new conditions and survive in your learning curve.

Just keep in mind that beautiful planted tanks and Procambarus clarkii don’t go together.

References:

  1. Red Swamp Crayfish (Procambarus clarkii). Ecological Risk Screening Summary. U.S. Fish and Wildlife Service, February 2011. Revised May 2015
  2. Crayfish,. Procambarus clarkii and P. zonangulus, Habitat Suitability. Index Model. Report: Final. Date: April 2017.
  3. Reproductive biology and life cycle of the invasive crayfish Procambarus clarkii (Crustacea: Decapoda) in diverse aquatic habitats of South-Western Spain. Fundamental and Applied Limnology / Archiv für Hydrobiologie. December 2008. DOI: 10.1127/1863-9135/2008/0173-0197
  4. Red swamp crayfish: biology, ecology and invasion – an overview. Nauplius 23(1): 1-19, 2015. DOI: http://dx.doi.org/10.1590/S0104-64972014002214
  5. Food choice by the introduced crayfi sh Procambarus Clarkii. Ann. Zool. Fennici 40: 517–528 ISSN 0003-455X. Helsinki 15 December 2003 © Finnish Zoological and Botanical Publishing Board 2003
  6. Burrowing activity of Procambarus clarkii on levees: analysing behaviour and burrow structure. Wetlands Ecology and Management. June 2019. DOI: 10.1007/s11273-019-09674-3
  7. Global Invasive Species Database (GISD) 2015. Species profile Procambarus clarkii. [Accessed 18 October 2019]
  8. Diet of the red swamp crayfish Procambarus Clarkii in natural ecosystems of the donana national park temporary fresh-water marsh (Spain). Journal of Crustacean biology, 18(1): 120-127, 1998
  9. Metal Accumulation in Crayfish, Procambarus clarkii, Exposed to a Petroleum-Contaminated Bayou in Louisiana. Ecotoxicology and environmental safety 37, 267–272 (1997). Article no. es971561
  10. Reproductive plasticity of a Procambarus clarkii population living 10°C below its thermal optimum. Aquatic Invasions (2015) Volume 10, Issue 2: 199–208. doi: http://dx.doi.org/10.3391/ai.2015.10.2.08
  11. Feeding of the exotic Louisiana red swamp crayfish, Procambarus clarkii (Crustacea, Decapoda), in an African tropical lake: Lake Naivasha, Kenya. Hydrobiologia 488: 129–142, 2002.
  12. Physiological and agonistic behavioural response of Procambarus clarkii to an acoustic stimulus. The Journal of Experimental Biology 216, 709-718. doi:10.1242/jeb.078865
  13. Distribution and reproduction of Procambarus clarkii in relation to water management, salinity and habitat type in the Camargue. Aquatic Conservation Marine and Freshwater Ecosystems. June 2014. DOI: 10.1002/aqc.2410
  14. Feeding preferences of the invasive crayfish, Procambarus Clarkii. BFPP/Bull. Fr. Pêche Piscic. (2007) 385: 07-20
  15. Inducing Molting by Eyestalk Ablation in the Red Swamp Crayfish, Procambarus clarkii from the Egyptian Freshwaters. American Journal of Life Sciences. Special Issue: New Horizons in Basic and Applied Zoological Research. Vol. 3, No. 6-1, 2015, pp. 69-75. doi: 10.11648/j.ajls.s.2015030601.20
  16. Heavy metals effects on life traits of juveniles of Procambarus clarkii. AIMS Environmental Science, 6(3): 147–166. DOI: 10.3934/environsci.2019.3.147 Received: 28 January 2019
  17. Courtship in the crayfish Procambarus clarkii (Girard) (Decapoda, Astacidea). Crustaceana. 1981

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