Blue Crayfish (Procambarus alleni): Ultimate Care Guide


Blue Crayfish (Procambarus alleni) is a freshwater crayfish that is endemic to Florida in the United States. Due to their vibrant blue coloration, they’ve gained popularity as a pet crayfish. In the aquarium trade, Blue Crayfish are also known as Electric Blue Crayfish, Sapphire Crayfish, Blue Lobster, and Florida Crayfish.

Their vivid blue color makes them very unique, and they can be interesting to watch. When fully grown they reach between 4 to 6 inches, and they will explore their surroundings with their large claws.

In addition to the fact that they look interesting, they are hardy and adapt well to a wide range of environments. Therefore, they’ve gained popularity worldwide as a pet crayfish.

This guide will help you understand how to take care of Blue Crayfish in detail.

Blue Crayfish Facts

  • In their natural environment, Blue Crayfish range in color from light brown to blue. However, the Blue Crayfish in the aquarium hobby have been selectively bred for their bright blue coloration.  
  • Blue Crayfish live in freshwater, but they can survive in saltwater for short period of time. They are known to survive for up two weeks in saltwater environments.  
  • In their native habitat in Florida, Blue Crayfish may experience dry periods. During the dry season, Blue Crayfish survive by burrowing deep into the mud. This prevents their body from getting dehydrated.
  • One pair of Blue Crayfish can spawn up to 100 to 300 eggs at once. Under the right conditions, they can multiply rapidly.
  • When a female Blue Crayfish releases urine, it can be a signal of aggression or the willingness to mate.
  • Fossils have revealed that all modern crayfish, including Blue Crayfish (Procambarus alleni), are descendants of prehistoric crayfish species that existed more than 100 million years ago.
Blue Crayfish
Blue Crayfish (Procambarus alleni)

How Rare is a Blue Crayfish?

Due to their popularity in the aquarium trade, Blue Crayfish are not rare and can be found for sale throughout the US and Europe. However, they’re less common in the wild and are only native to the freshwater pools and everglades of Florida.

Procambarus Alleni is listed on the International Union for Conservation of Nature’s red list of threatened species but is categorized as ‘least concern.’ The endemic population of blue crayfish is considered to be stable and they can be found in two protected areas; Big Cypress National Preserve and the Everglades National Park. There are plans in place to restore and preserve these habitats for the crayfish and other native species. As a result, their numbers are likely to increase in the coming decade.

Currently, there are no established populations of blue crayfish outside of Florida. However, because they’re sold globally it’s likely that some may escape and set up colonies. Some European countries already have restrictions and guidelines in place to prevent foreign crayfish species from invading their waterways.

Do Blue Crayfish Make Good Pets?

Blue crayfish make excellent pets; they’re relatively low maintenance and have a stunning appearance. However, they have specific requirements that make them unsuitable for some beginners. They can also become aggressive with their tank mates and most owners prefer to keep them in solo setups.

If you’re an experienced aquarium keeper and you want an aquatic creature that’s interesting to watch as they move around, a blue crayfish is ideal. Still, it’s worth bearing in mind that they’re nocturnal and love to burrow. You’ll still see them fairly often, but they will do most of their feeding and scavenging at night.

This species of crayfish is particularly hardy and will adapt to a variety of conditions. If you want them to live for longer or intend to breed them then it’s advisable to keep them in gently moving water.

When you get the conditions right, you’ll find that you have a tolerant, hardy pet that will even allow you to handle them occasionally.

Blue Crayfish Care

Keeping blue crayfish can be incredibly rewarding but it’s essential to follow a few guidelines and invest the time and effort to set up your tank correctly. Let’s take a closer look at the specifics so you can be prepared for your new aquatic pet:

Temperature for Blue Crayfish

When living in the wild in Florida, blue crayfish are exposed to average temperatures between 73°F (23℃) and 86°F (30℃). In captivity, the ideal tank temperature is 70°F (21℃) but they’ll be fine in anything from 68°F to 79°F (20℃ to 26℃).

At these temperatures, depending on where you’re located, you likely won’t need an aquarium heater. In fact, because crayfish are used to relatively cool moving water, we recommend that you avoid heated tanks if possible.

Water pH for Blue Crayfish

Wild blue crayfish prefer a neutral water pH of about 7.28. In your home aquarium, they will be comfortable in anything from 6.5 to 7.5. A pH testing kit is a useful item to have and it will ensure that your crayfish aren’t unduly stressed by a drop in pH.

Remember to test the water when your tank is completely set up because items like plants, rocks, substrate and even aeration machines can alter the water pH. Over time the water in your tank will naturally drop the pH level so it’s important to change the water at least once a week.

If you forget and leave it for several weeks, change half a tanks worth of water first and then again 24 hours later. This will allow the pH to change steadily and prevent your crayfish from being affected by an abrupt pH change.

Blue Crayfish Size & Growth Rate

An adult blue crayfish kept in an aquarium can reach 4 to 5 inches long. If the conditions are right and they get plenty of food, juvenile crayfish can grow very fast. They can double their size in just a couple of weeks, and some will achieve close to full size in only 3 to 4 months.

If you buy your crayfish as a baby, it will likely measure between half an inch and an inch. As they get older and reach maturity their growth rate slows significantly.

Some healthy specimens have been found in the Florida everglades measuring up to 7 inches long. This suggests that the closer you can replicate their natural habitat, the better the chance that they’ll live a long and healthy life.

How Often Does a Blue Crayfish Molt?

How often a blue crayfish molts depends on how healthy it is, the tank conditions and how much it eats. It’s common for a healthy blue crayfish to molt between 6 and 10 times their first year and 3 to 5 times during its second. Molting continues to get less frequent as it gets older.

Some crayfish owners report that Procambarus alleni molt on average every 2 to 8 weeks but it can be more frequent when they’re very young. In some cases, they’ve been observed to molt up to three times in one week.

During a molt, the tough exoskeleton is shed and the new one is soft for a few hours. This makes them vulnerable to attack and damage. When you’re planning your tank it’s essential that you provide small caves or pipes for them to find protection during this time.

Tank Size for Blue Crayfish

To ensure that a single blue crayfish stays happy and healthy it should be kept in a tank no smaller than 30 gallons. Young crayfish can still thrive in slightly smaller spaces, but adults need lots of room to move around and explore.

If you plan on keeping more than one crayfish or want to stock a community aquarium you will need to look at tanks of 50 gallons or more. With enough space, the crayfish can hide or burrow into the substrate. This will reduce the chances of them becoming too aggressive and attacking other fish or crustaceans.

Blue Crayfish Food & Diet

Blue crayfish are omnivorous bottom feeders and thrive on a mixture of different types of foods including shrimp pellets and vegetables. If you feed your crayfish daily and ensure that they have enough protein in their diet they will be less likely to attack any other crayfish or tank mates.

Most of their daily food should be dried shrimp sinking pellets. These contain a variety of nutrients and will allow them to grow, molt and develop a strong exoskeleton. Apply one or two shakes of the pellets to areas of your tank that your crayfish loves to explore.

To add variety, you can supplement the pellets with small amounts of other foods such as frozen daphnia, frozen bloodworm or vegetables. Vegetables like lettuce, cucumber, cabbage, peas and carrots make an ideal treat.

All vegetables should be peeled and blanched in boiling water for 1 to 3 minutes then plunged into ice-cold water. This process removes any toxins or contaminants without destroying the nutrients.

It’s important that you avoid using live or raw shrimp because they can carry diseases that are harmful to crayfish. Also, avoid overfeeding by watching how much they eat and removing anything that’s not been eaten after 24 hours. Then adjust the amount you give them next time to ensure they’re getting enough to thrive but not too much.

Blue Crayfish Lifespan

Most blue crayfish kept in aquariums will leave at least 2 years, but they can reach 5 or 6 years if you carefully maintain their environment and keep them healthy and disease-free.

To help your blue crayfish make it to the ripe old age of 6, there are several things you can do:

  • Ensure they have a large enough tank with some places to hide.
  • Include a bubbler or pump to create some movement that keeps the water oxygenated and replicates their natural habitat.
  • Regularly change the water to maintain optimum pH levels.
  • Feed them a varied diet including protein and vegetables.
  • Take steps to prevent disease including removing uneaten food and not feeding them uncooked shrimp.

Tank Setup for Blue Crayfish

The setup for a blue crayfish should include a fine, sand-based substrate and several caves. You will also need an efficient aquarium filter to ensure that the water is kept clean. Crayfish prefer gently moving water so you may like to include a bubbler or additional pump.

It’s essential that you provide enough places for your crayfish to hide when they’re molting. You can make caves from almost anything including old pots, rocks, bogwood or purpose-made fish hides.

When making any aquarium set up it’s tempting to include lots of attractive plants; however, with blue crayfish, this is best avoided. They love to tear plants down and chew them, so they’ll be unlikely to last long.

The final thing to consider when designing your crayfish tank setup up is that they love to try and escape. If possible, opt for a completely enclosed tank but if not, you will need to add your own covering. Another useful idea is to encase your pump in a simple plastic housing. This will prevent your crayfish from using any pipes and the pump itself to assist it in its bid for freedom.

Breeding Blue Crayfish

If you have a large enough tank to keep an adult male and female blue crayfish safely, they may become interested in mating. The female will attract the male by releasing urine into the water. They will then become aggressive towards each other and fight before getting close enough to mate.

When the female’s eggs have been fertilized, she will keep them safe under her tale. You should then move her to a separate tank. About a month later the baby crayfish will hatch. At first, they will be carried around on their mum. In a couple of days, you’ll see them begin to move around independently.

At this point, there is a risk that she may turn on them and eat them so you can move her back to the first tank. You can then feed the baby crayfish on small amounts of vegetables and shrimp pellets in the same way as you would for adults.

As they start to grow you will need to separate the babies and move them into larger tanks to stop them from eating each other.

Male vs Female Blue Crayfish

Male blue crayfish are generally slightly larger than the females and have noticeably bigger claws and slimmer tales.

Underneath the tails of blue crayfish, you’ll see several pairs of small appendages. These are called swimmerets. Males have a larger, firmer pair of swimmerets that assist with sperm delivery. Female blue crayfish also have a small hole on their tail which allows them to release their eggs.

Diseases Common to Blue Crayfish

Blue crayfish are hardy creatures and disease is relatively rare in aquarium bred specimens. However, they’re particularly susceptible to illness if their tank conditions aren’t correct. It’s important to keep the tank clean because they don’t tolerate excess levels of ammonia or nitrates.

Wild colonies of blue crayfish do occasionally suffer from a disease called crayfish plague. This can result in missing eyes or limbs and the appearance of strange growths. It’s transmitted by crayfish and other fish and can infect aquarium bred crayfish, although with good hygiene and reputable breeders this is relatively rare.

Tank Mates for Blue Crayfish

If you’ve not kept crayfish before we recommend that you start with one in a tank on its own. However, if you’re more experienced you may want to take things to the next level and introduce some other species:

Are Blue Crayfish Aggressive?

Blue crayfish are known for their aggression and they’re likely to attack any other fish they can get hold of, including other crayfish and even their own offspring.

Examples of Compatible Tank Mates

Blue crayfish are likely to attack and eat other fish but luckily, they move relatively slowly and tend to stay on the bottom of the tank. This means that fast-moving fish that prefer to swim in the middle or top of the tank make the best tank mates.  

Mid-level loving fish like tiger barbs and neon tetras will be unlikely to get caught and eaten. Also, fish that prefer the surface and like to stay active include hatchet fish, zebra danios, giant danios, furcata rainbowfish. All of these are unlikely to fall prey to your blue crayfish but bear in mind that any fish that gets too close or becomes ill may become crayfish food.

Examples of Incompatible Tank Mates

Any aquarium creatures that spend time on the bottom or move slowly are incompatible tank mates for a blue crayfish. This includes shrimp, snails and even some small catfish.

Blue Crayfish and Betta fish

Betta fish and blue crayfish are not suitable as tank mates. If your betta is particularly aggressive it will likely attack your crayfish as well as anything else in the tank. In most situations, a blue crayfish will be unlikely to survive this encounter. However, if it gets the chance a blue crayfish will just as likely attempt to attack and eat your betta fish. If you do decide to go ahead with this pairing, ensure that your crayfish has lots of hiding places and the tank is at least 50gallons.

Blue Crayfish and Goldfish

Goldfish and blue crayfish are not compatible tank mates. Even though goldfish can grow quite large and are generally active swimmers they may still be attacked by a blue crayfish when they venture to the bottom of the tank. In most situations, this is unlikely to happen but if the goldfish becomes ill or starts to hang around at the bottom of the tank it’s unlikely to last long.

Blue Crayfish and Pleco

Plecos are a type of bottom-feeding catfish and are not suitable as a tank mate for a blue crayfish. Because plecos spend a lot of time on the bottom of the tank, they risk being attacked. Also, if they can get close enough to the crayfish they may choose to strike first.

Blue Crayfish and Cichlid

Cichlids are not compatible with blue crayfish. Both species are known for their aggression and will attack if given the chance. It’s unlikely that any crayfish will last long in a tank with cichlids. However, if you opt for dwarf cichlids you may have a more harmonious aquarium.

Conclusion

Blue crayfish display beautiful bold colors, are low maintenance and can be great fun to watch as they dig around in the substrate. However, they can also be challenging and are best kept in solo setups. If you decide that you have the necessary equipment and experience to take one on, you’ll be rewarded with a unique pet and hours of enjoyment.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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