All About Australian Redclaw
Australian Redclaw Crayfish, also known as the Cherax Quadricarinatus, is a new
and promising species for aquaculture enthusiasts. In the state of Florida, you must have a Florida Aquaculture License to own Australian Redclaw Crayfish.
The Redclaw Crayfish is very
similar to the native American species, but it can grow to a HUGE size
comparable to a lobster! This means the species has considerable potential for
commercial culture. The fact that it can withstand low oxygen
levels and thrives in warm waters makes it well-suited to aquaculture and
aquarium life as well. The Australian Redclaw Crayfish does best when water
temperatures are between 75˚ and 85˚ F.
The Redclaw Crayfish is a tropical freshwater crayfish native to Australia.
They are often called "freshwater lobsters" because of their physical
resemblance and large size. They are valued as both a food source and as an
The Redclaw Crayfish is the more common species of "yabby" in the
Northern Territory and is found in most lakes and rivers in North Australia as
it thrives in tropical freshwater environments. In nature, these creatures are
often found under roots or rocks where they hide from predators.
Crayfish have a smooth, lustrous shell that is deep blue to green in color.
Males have a bright red coloring on the margins of their large claws, thus the
name "Redclaw." The blue color intensifies when the water is clean;
the animals are a more green/brown when left in brackish water. Additionally,
the blue color intensifies as the crayfish matures.
crustacean is one of the largest freshwater crayfish in the world. Average
market sizes of 50 to 150 grams (1 pound - 454 grams) are achievable in six to
12 months, though they can reach up to 600 grams each.
cooked, they present as bright red, typical of premium
crustaceans. Redclaw Crayfish is considered a delicacy, comparing
favorably with other commonly eaten marine crustaceans. The meat is arguably
more healthy than traditional seafood, however, since it is low in fat,
cholesterol and salt.
Redclaw lobsters are scavengers. They are a bottom dweller and will eat anything
they come across, as they are opportunistic eaters. They will eat all of the
leftover food your fish miss, as well as detritus and other waste off the bottom
of your aquarium. Although this lobster will eat dead or dying fish as
well, it is normally too slow to catch healthy fish.
A healthy diet includes both vegetables and animal proteins. The primary diet
should include plant matter, worms, brine shrimp, bloodworms, or insect larvae,
and can include vegetable matter waste from aquaponics systems such as lettuce,
shredded carrots, zucchini, etc. Adding a high-protein fish or shrimp sinking
pellet, flake food, and dried algae is also recommended.
To be successful in the maintenance and reproduction of brood stock in indoor
holding systems, be sure to:
* Select healthy mature adults
* Maintain warm temperatures (preferably between 75˚ and 85˚ F)
* Maintain good water quality
* Provide proper nutrition
* Isolate berried females (females carrying eggs) to hatching tanks
In a hatchery, Redclaw can spawn almost continuously throughout the year if
conditions are suitable. They generally reach sexual maturity by the age of six
to 12 months. As noted earlier, mature male Redclaw develop a distinctive red
or orange patch on the outside margin of the claws; animals of this same size
without the reddish claw patch are usually females. The sexes are best
identified, however, by examination of the genital openings on the underside of
the cephalothorax at the base of the walking legs. Females have a pair of
genital pores at the base of the third pair (counting from the head) of walking
legs. Males have a pair of small genital papillae (small projections) at the
base of the fifth pair of walking legs.
Individual females do not spawn when going through a growth
phase (i.e.,moulting). Each female will produce 100 to 1,000 eggs per spawn
depending on her size and general health. The first spawn of young females
usually has fewer eggs than latter spawns. Newly spawned eggs average 10 eggs
per gram of female. About 30 percent of the eggs are lost during incubation,
resulting in an average of 7 eggs (that hatch) per gram of female. For example,
a female weighing 3 ounces (85 grams) would produce about 600 eggs. This can be
used to estimate the number of eggs a female of a given size will produce.
Broodstock and Hatchery
Mature broodstock Redclaw crayfish can be kept at a density of one to two
animals per square foot of tank bottom. The ratio of females to males in each
tank should be between one and four females for each male. Good spawning
success has occurred using tanks with water depths of 1 to 3 feet. Small
rectangular tanks of 15 to 20 square feet have been used successfully, as well
as large circular tanks of 15 feet in diameter with 1 to 3 feet of water. For
example: A 20-square-foot tank that is 2 feet deep could be stocked with five
to 10 males and 15 to 30 mature female Redclaw. Broodstock tanks should
maintain a water temperature between 75˚ and 85˚ F for
Breeding tanks should be checked every one to two weeks for
berried females. Once the fertilized eggs are affixed to the female's pleopods,
"swimmeretts" situated on the underside of the tail, It is highly
recommended that berried females be moved to a separate tank. Berried females
should be carefully netted, keeping them with their abdomen curled around the
eggs during transfer to hatching tanks. (to prevent egg loss). Incubation takes
approximately six weeks and the newly hatched juveniles rapidly become
independent. The hatching tank will then become the nursery tank for raising
the young Redclaw.
While Redclaw Crayfish have a low
level of aggression, "homes" are essential. PVC pipe sections in
multiple sizes, mesh bags, burlap, rocks, or anything that the crayfish can
climb through and hide in for shelter will suffice. Young crayfish will moult
many times during their first year of life, as they grow quickly, while mature
Redclaw will moult only once or twice a year. The shed exoskeleton (moulted
shell ) is used as a source of calcium and is typically eaten by its owner or
other crayfish. Redclaw in tanks can handle a temperature range from 60˚ to
90˚ F. Temperatures below 55˚ and above 95˚ F will
result in casualties.
Australian Redclaw As Pets
Redclaw Crayfish, with their exotic coloration, are easy and fun to raise
in your tropical aquarium as unique pets. They are less aggressive than most
crayfish, and reproduce rapidly and easily. One Redclaw Crayfish can inhabit a
25-gallon aquarium, while a 40-gallon aquarium with plenty of caves and space
to move around can support two. The larger Australian Redclaw Crayfish requires
a tank that is at least 40 inches long and 20 inches deep.
The ideal tank environment consist of about 5 inches of
aquarium sand or gravel on the bottom with pipes, tunnels, decorative rocks and
caves. You can plant hardy plants in the aquarium, but small, weaker plants
won't survive. You will want to make sure the aquarium has a filter to keep the
aquarium clean, and combine that with periodic partial water changes. Use test
strips to monitor the pH levels which should be between 6.5 and 8. When
cleaning the tank, test the pH before and after changing the water to ensure
levels remain within the proper range. Use an aquarium heater and thermometer
to measure the water temperature and maintain the aquarium between 77˚ and
90˚ F. Temperatures below 55˚ or above 95˚ will
result in casualties. Test the water hardness, as well; they need hard water to
thrive. You can add limestone to make the water harder if necessary.
Plenty of cover should be included in the aquarium,
including both rocks and plants, though the plants will not last long as the
crayfish get larger. After moulting the crayfish is vulnerable to attack and
consumption by others. If the exuvia (shed exoskeleton, moulted shell) is
removed from the tank after shedding, the crayfish will likely die as this shed
should be consumed for vital calcium. However, If your water has enough calcium
in it, this will not be an issue.
* Redclaw Crayfish are excellent escape artists! If the water level is near
the top of the tank, if you have rocks and decor large enough for them to reach
the surface, or if equipment such as airline tubing or heater cords extend over
the side of the tank, they will climb out. To reduce the likelihood of escape,
equipment should be suspended overhead so that it does not touch the sides of
the tank. If housed in an aquarium, a lid may be required.
The Redclaw Crayfish or Cherax Quadricarinatus, is also known by several
other common names including: Australian Redclaw Crayfish, Queensland Redclaw,
Redclaw, Tropical Blue Crayfish, Freshwater Blueclaw Crayfish, Redclaw
Crayfish, Blue Lobster, Australian Crayfish, Australian Crawfish, Freshwater Crayfish,
North Queensland Yabby, Yabby, Yabbie and Queensland Redclaw to name a few.
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