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Blue Crayfish Care Guide and Tank Setup (Temperament, Tankmates, and Breeding)

The blue crayfish (also referred to as the electric blue crayfish or the sapphire crayfish) is found primarily in the St. John’s River in Florida. In the wild, this species ranges in color from brown-tan to red-orange and blue but has been selectively bred to achieve a vibrant shade of cobalt blue for the aquarium trade. This makes them a brilliant addition to almost any freshwater tank.

This article will outline everything you need to know as an aquarium hobbyist about basic blue crayfish care. I’ll explain how to maintain, breed, and raise this species in captivity as well as how to setup the aquarium, what to feed them, how big they get, what they’re temperament is like, and which fish make the best tankmates.

And now, let’s dive deeper into the fascinating aquatic world of the awe-inspiring blue crayfish…

Blue Crayfish Overview

Behavior: semi-aggressive; highly aterritorial

Breeding: egg carrier

Care level: easy

Diet: omnivore

Family: Cambaridae

Lifespan: up to 5 years

Origin: freshwater river basins in Florida, U.S.A

Size: 2 to 4 inches

Tank size: 30-gallon minimum

Blue Crayfish Natural Habitat

Blue crayfish are found naturally in freshwater ditches, streams, marshes, wetlands, and flood plains – mainly in Florida just south of the panhandle. While it’s believed that blue crayfish can also be found in California, France, and Germany, these are though to be colonies introduced to the regions by breeders of the aquarium trade.

Blue Crayfish Appearance and Size

Blue crayfish, contrary to the name, can morph into other colors besides their brilliant cobalt shade. They can contain hues of red, orange, and brown with speckling that appears as dots or light patches. The average size of an adult blue crayfish in captivity is approximately 4 to 5 inches, though some reports of this species growing to lengths of up to 7 inches in the wild are worth mentioning.

Blue Crayfish Behavior and Temperament

Blue crayfish, unlike other invertebrates, aren’t shy can be both aggressive and territorial. They’re highly active in captivity and like to move about the tank frequently. While this behavior makes them a joy to watch, it also can spell trouble for smaller, weaker tankmates who invade their space. For the most part, however, when not foraging along the substrate, these creatures will hide out in caves or behind rocks.

blue crayfish in aquarium

Blue Crayfish Diet

Blue crayfish are omnivorous and will typically eat whatever they can! While they prefer to eat plant-based foods like invertebrate pallets or blanched vegetables, they’ll also nibble on fish food, algae wafers, and even dead or dying fish and snails. As opportunistic feeders that like to forage along the substrate, you should be sure to feed them every day to prevent them attacking their tankmates.

Blue Crayfish Lifespan

Blue crayfish in captivity usually live up to 5 or 6 years in captivity with the proper care, of course. They reach full-grown lengths in as little as 3 to 4 months and will seek out a mating partner to reproduce within the first year of life. The key to their longevity is maintaining a clean, safe aquatic environment as well keeping the water parameters stable and accurate.

Blue Crayfish Required Water Conditions

The ideal water parameters for healthy blue crayfish include a temperature between 65- to 75-degrees Fahrenheit and a pH level of 6.5 to 7.5. The hardness should be 4 to10 dGH with dissolved solids ranging from 100 to 300 ppm. Though blue crayfish are very hardy and can adapt to less-than-perfect water conditions, stability is vital when it comes to water chemistry – even more so than exact values.

Blue Crayfish Fish Tank Size

Blue crayfish are highly active and need a large area in an aquarium to forage and explore. Therefore, they require a minimum tank size of 30-gallons. Regardless of their ability to help keep the aquarium clean and free of waste, they still require enough room to move about freely and claim their territory. This will prevent them from becoming hostile to space-invading tankmates.

If you intend to keep blue crayfish with other fish or invertebrates, you must provide plenty of hiding places such as plants, rocks, driftwood, and caves. This species becomes vulnerable when molting (shedding their exoskeleton) so adding extra areas of cover is crucial to their survival. Since this species prefers tropical-like conditions, be sure to include a heater, filter, pump, and LED aquarium light.

Blue Crayfish Tank Setup

To setup a tank for blue crayfish, follow these 8 steps:

  1. Get a 30-gallon aquarium as well as all necessary equipment including a lid with an LED light, a heater, a filter, a pump, and water conditioner.
  2. Place the tank in an area that doesn’t receive too much direct sunlight since this can alter water temperature and increase algae growth.
  3. Add substrate to the bottom – fine, black-colored sand is recommended as it’s easy for crayfish to scoot around on as well as makes their cobalt blue color pop!
  4. Place decorations in the tank – include plenty of plants, rocks, driftwood, and caves to provide safety and cover for blue crayfish.
  5. Treat the water to neutralize chlorine – follow the instructions provided on the bottle. Look for a product like API Water Conditioner available at your local fish store on online through Amazon.
  6. Cycle the water completely – this takes anywhere from 6 to 8 weeks.
  7. After the water has been cycled, add blue crayfish to the tank – make sure to acclimated it to the tank first.
  8. Introduce tankmates once blue crayfish have been established – fast-swimming fish that prefer to remain in the middle of the tank are recommended.

Best Tank Mates for Blue Crayfish

Blue crayfish can get aggressive and territorial if they feel their space is being invaded. Therefore, the best tankmates for this species are fast fish that prefer to swim in the middle of the tank. That way, they won’t bother the bottom-dwelling crayfish. I recommend danios, guppies, neon tetras, tiger barbs, rosy-red minnows, and hatchetfish.

Since blue crayfish won’t hesitate to feast on smaller tankmates, slow-moving fish or crustaceans that lurk along the substrate are not good choices. These include betta fish, hermit crabs, apple snails, and even plecos. On the plus side, however, if you have a trumpet snail problem in your tank, blue crayfish should take care of this for you by eating the majority!

Breeding Blue Crayfish

Blue crayfish are egg carriers. They reach sexually maturity in the first year of life and will immediately look for a partner to reproduce with. This species is difficult to sex but if you look at the swimmerets, you’ll be able to distinguish male from female. The males have swimmerets that extend past their bag legs whereas the females don’t.

To successfully breed blue crayfish, be sure to feed them high quality foods and keep the tank as clean as possible. Slightly warmer water will also help encourage breeding behavior. Mating begins with the male depositing a sack of sperm onto the female. She then passes her eggs through the sperm sack at which point they become fertilized.

After fertilization, the eggs are kept safely under the tail of the female. It’s now that the female should be moved to a separate breeding tank.  About 4 weeks later, the eggs will hatch and baby blue crayfish will emerge. The female will continue to care for her offspring for the first little while. However, she should be moved to the main tank eventually to prevent her from eating her young.

Caring for Blue Crayfish Offspring

To care for blue crayfish offspring, begin by setting up the breeder tank. Spread soft sand along the bottom for the youngsters to dig/burrow in. Make sure the water is properly treated with a conditioning agent to dechlorinate it. Add a sponge filter to help aerate the tank and keep it clean. And don’t forget to include a cover as blue crayfish are skilled escape artists! Consider adding some aquatic plants as well.

To feed blue crayfish offspring, simply crush fish food pellets or algae wafers small enough to fit into their mouths. They’ll also accept tiny pieces of blanched vegetables such as cabbage or lettuce leaves. As crayfish grow, make sure to rehome the larger ones as soon as possible since they’ll feed on their smaller siblings.

Blue Crayfish Cost

The average cost for blue crayfish is between $20 to $50 US, depending on the size, color, etc. In some instances, the change of season as well as breeding numbers will affect their pricing. Your best bet is to purchase blue crayfish at your local fish store/pet shop, though you may need to inquire in advance as this species could be a special order.

Common Blue Crayfish Diseases

Blue crayfish, though generally hardy in nature, can succumb to illness and disease just like other freshwater aquarium fish. Poor water conditions and an unclean environment are the most likely culprits. This species doesn’t tolerate high levels of ammonia or nitrate so it’s imperative that you do testing and partial water changes to prevent toxins from building-up.

Blue crayfish, if wild-caught, can carry natural diseases which can negatively affect all other aquatic creatures sharing the same captive environment. Crayfish plague is one such illness with typical symptoms ranging from lethargy to loss of coordination and refusing to eat. Currently there isn’t a known cure or treatment for crayfish plague and will ultimately result in death.

large blue crayfish

Blue Crayfish Special Recommendations

Special recommendations for blue crayfish include as large a tank as possible (30-gallons, but bigger is better). As well, this species should be kept with fish that prefer to reside in the middle of the tank and won’t invade their territory along the bottom. As many hiding places as you can provide is beneficial since crayfish need places of refuge when molting.

How Often do Blue Crayfish Molt?

Molting refers to an invertebrate’s ability to shed its endoskeleton. Infant blue crayfish will molt every few days whereas juveniles do so once every 7 to 14 days. Adult crayfish molt less frequently – anywhere from 30 to 40 days. It’s interesting to note that this species will often eat its own endoskeleton after it’s been shed!

Are Blue Crayfish Hardy?

Blue crayfish are among the hardiest of invertebrate species. They adapt well to almost any freshwater environment and make a good choice for beginner aquarium hobbyists. The only things they require are a clean aquatic environment and sufficient food. Be forewarned that they don’t react well to high levels of ammonia which is why weekly partial water changes (at least 25%) and regular testing are a must.

Are Blue Crayfish Nocturnal?

Blue crayfish are a nocturnal species and thrive in long hours of darkness. For this reason, you should invest in an LED light with an ambient or ‘blue light’ feature to mimic moonlight and create a more obscure aquatic environment. Daylight hours shouldn’t exceed 8 hours and it’s best not to place the tank too close to a window.

Pros and Cons of Blue Crayfish


  • very hardy and recommended for amateur aquarium hobbyists
  • can adapt to almost any freshwater aquarium environment
  • help keep the tank clean and free of snail infestations
  • brilliantly blue colored making them an eye-catching attraction
  • active nature makes them a joy to observe in captivity


  • can get aggressive and territorial, especially when kept in too small of an aquarium
  • will eat smaller, weaker tankmates (even dead or dying fish), if given the chance
  • won’t tolerate increases in ammonia levels which requires additional tank maintenance
  • can be costly to purchase at times, depending on the circumstances
  • can bring diseases into an aquarium if wild-caught

Final Thoughts

To summarize, blue crayfish (aka electric blue crayfish or sapphire crayfish) are a type of freshwater invertebrate originating in the St. John’s River in Florida. Their brilliant coloring, energetic behavior, cleanly nature, and hardy disposition make them a joy to observe and a long-time favorite among freshwater aquarium hobbyists.

I hope this article has provided you with the information you seek regarding how to successfully keep, breed, and raise blue crayfish in captivity. Thanks for reading and good with your aquarium hobby.

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