Red Claw Blue Lobster (Cherax quadricarinatus)

Red Claw Blue Lobster for a secure freshwater aquarium

Red Claw Blue Lobster, Cherax quadricarinatus, is a large Australian freshwater crayfish with powerful claws, an inquisitive bottom-dwelling nature and colour that can combine blue, green, bronze and red. It is also called Red Claw Crayfish, Australian Red Claw Crayfish or Blue Lobster in the aquarium trade. Despite the lobster name, this is a freshwater crayfish, so its aquarium must be planned around climbing, digging, moulting and territorial behaviour rather than ordinary community-fish care.

This is an absorbing animal for a keeper who wants a visible, interactive crustacean and is prepared to build the aquarium around it. A settled individual may patrol the front glass, move small pieces of decor, carry food back to a cave and become active when it recognises the feeding routine. That strength and curiosity are also why a tight lid, stable rockwork, several shelters and a mature filter are essential.

Choose between the live size options shown beside the current price and availability. Both are juveniles and both need the same adult plan. One quantity means one unsexed crayfish at approximately the selected size, with natural variation between living animals. The gallery shows representative appearance and habitat context; it does not promise the exact individual, sex, colour intensity or adult shade that will be dispatched.

First-time customers can use WELCOME10 where the code is eligible, and qualifying live-animal deliveries are covered by our Live Arrival Guarantee when the delivery terms are followed. Please finish the aquarium, cycle the filter and secure every opening before ordering. A young animal may look compact, but it should never be bought for a temporary container with no credible adult home.

Identity, colour and adult appearance

Cherax quadricarinatus is native to warm freshwater habitats in northern Australia. Its shell colour is naturally variable. Juveniles sold as blue forms can be bright cobalt or turquoise, while others show olive, bronze or darker blue tones. Colour can change after a moult and can be influenced by age, genetics, diet, background, lighting, water chemistry and stress. A temporary pale or dark phase is therefore not automatically a health problem.

The common name comes from the soft red patch on the outside of the large claw in mature males. Young animals may not show it clearly, and females do not develop the same conspicuous patch. At small sale sizes, sexing by a photograph or body shape is unreliable. We do not promise a male, female, pair or chosen colour grade.

Plan around adult body mass, not just length. Around 18-20 cm is a sensible common planning range, while specialist records note that exceptional males can approach 30 cm. That upper figure is not the expected size of every animal, but it explains why a wide floor area, strong filtration and robust furnishings matter. A tall narrow tank can hold many litres while still giving a crayfish very little usable territory.

Legal and responsible keeping

Current GOV.UK guidance for England and Wales identifies Red Claw Crayfish, Cherax quadricarinatus, as the crayfish exception that can be kept without a licence when it is held in an indoor aquarium for ornamental use. That wording matters. It does not make outdoor ponds acceptable, does not permit release, and does not automatically describe the rules in Scotland or Northern Ireland.

Keep this animal in a heated indoor aquarium and prevent escape. Never release it into a river, canal, lake, pond, drain or flood-prone outdoor container. Non-native crayfish can affect habitats and carry disease even when the keeper believes a local waterway looks suitable. If you can no longer care for the animal, arrange responsible rehoming through an experienced aquatic keeper or retailer.

Rules can change and circumstances differ by nation, premises and intended use. The linked official guidance is the right starting point for England and Wales; keepers elsewhere should check the authority responsible for non-native species before ordering. The animal's accepted identity should be retained with its care records because common names such as Blue Lobster can be applied inconsistently in trade.

Tank size and floor-space planning

For one Red Claw Crayfish, our cautious long-term recommendation is at least 120 litres with roughly 90 cm or more of frontage; 180 litres or more is preferred for an adult. This is a practical aquarium recommendation based on adult size, territory, waste production and usable floor area. It is not a legal threshold or a measurement taken from the wild.

A smaller mature aquarium can serve briefly as a carefully managed juvenile grow-on tank, but it is not a reason to postpone the adult plan. The animal will not stay 4-7 cm. Moving a territorial crayfish after it has outgrown its aquarium can be difficult, particularly if a larger replacement tank is not cycled. Set up the long-term home first whenever possible.

Footprint is more important than height. A long, wide aquarium provides room for separate feeding and shelter zones, while a tall display may offer little more than one contested patch of substrate. The aquarium care planner can help organise the water and maintenance requirements, but its output should be interpreted alongside the adult floor-space guidance here.

Escape-proof lid and safe layout

A secure lid is essential. Crayfish can climb filter pipes, airline, heater cables, textured backgrounds and decor that reaches towards the surface. Cover cable notches and pipe cut-outs without blocking necessary ventilation, keep the waterline below the rim and inspect the lid every time equipment is moved. A gap that looks too small can become usable when the animal braces its legs and claws against nearby equipment.

Place heavy rocks directly and securely so digging cannot undermine them. Avoid unstable piles, narrow crevices that may trap a newly moulted animal and sharp ornaments that can damage soft shell. Wood and caves should be large enough for the crayfish to turn around as it grows. Several shelters are better than one perfect-looking central cave because the animal can choose a retreat during different stages of the moult cycle.

Protect the heater with a suitable guard or place it where direct contact is unlikely. Cover filter intakes that could trap a limb without starving the filter of flow. Keep electrical equipment in good condition and use a drip loop. A basic freshwater aquarium setup guide covers the normal foundations; the extra requirement here is designing every opening and furnishing for a strong climbing crustacean.

Water parameters and stability

A useful aquarium target is 22-26 C, pH 7.0-8.5 and approximately 5-22 dGH. These broad values are not an invitation to let the aquarium swing from one end to the other. Choose a stable point within the overlap of your source water and the animal's needs, then avoid sudden changes during maintenance or acclimation.

Redclaw is a warm-water species. Commercial growth data often cites 26-29 C, but that is production context rather than a requirement to keep a home display at the upper edge. Higher temperature also increases metabolism and oxygen demand. A stable 22-26 C aquarium offers a sensible core range while avoiding cold rooms and summer overheating.

Mineral content matters because the new shell must harden after a moult. Very soft, acidic water can make this more difficult. Test the source water before adding products, and avoid adjusting chemistry by guesswork. Our aquarium water chemistry guide explains pH, GH and KH separately so that a number is not corrected with the wrong additive.

Filtration, oxygen and cycling

A large crayfish creates far more waste than a small ornamental shrimp. Use a mature biological filter sized for the adult animal, not only the juvenile arriving today. The Aquael Ultra External Filter is one example of a filter range to compare against the actual aquarium volume and required turnover. Equipment choice still needs to account for hose security, intake protection and the ability to service media without destabilising the tank.

Provide steady surface movement and good gas exchange. An Aquael OxyPro Air Pump can add aeration where the aquarium and filter arrangement require it, but bubbles do not replace biological filtration or water changes. Warm water holds less oxygen, and decomposing food consumes more, so feeding control and surface movement work together.

Do not add the crayfish to a tank that has only been filled for a few days. A cycled aquarium has established bacteria that process ammonia to nitrite and then nitrate. Confirm zero ammonia and nitrite under a realistic bioload before delivery. The Tetra Ammonia Test Kit can support routine checks, alongside nitrite, nitrate, pH, GH and KH tests appropriate to the aquarium.

Moulting and shell care

A crayfish grows by shedding its old exoskeleton. Before a moult it may eat less, hide more and become less active. During and immediately after the shed, the new shell is soft and the animal is vulnerable. Do not pull it from a cave, handle it, rearrange the aquarium or introduce companions during this period.

Leave the shed shell in the aquarium unless it is fouling the water or there is another clear reason to remove it. The crayfish may consume much of it and recover minerals. The empty shell can look alarmingly like a dead animal, so confirm the crayfish is hiding before assuming the worst. A complete shed usually includes delicate antenna and leg shapes.

Good moults depend on more than one supplement. Stable pH and hardness, varied nutrition, good oxygen, low waste and a secure retreat all contribute. Repeated incomplete moults, a shell that remains soft, unusual limb loss or persistent weakness should trigger a review of water chemistry, diet, temperature, recent treatments and possible harassment.

Feeding an opportunistic omnivore

Cherax quadricarinatus is an opportunistic omnivore. Use a quality sinking crustacean food as the foundation, then rotate algae-based foods, safe vegetable matter, leaf litter and measured protein foods. Variety is more useful than repeatedly offering one rich food. Feed amounts the animal can finish and remove leftovers before they soften into the substrate or filter.

The Cambarellus-VITAL Crayfish Food is an optional crustacean food to compare for pellet size and ingredients; it should form part of a varied plan rather than the entire diet. Green Algae Wafers can contribute plant material, while Crustacean Frozen Fish Food can be used sparingly as a protein-rich rotation food. Remove any thawed food that is not eaten promptly.

Offer food near the shelter after lights dim if a new arrival is shy. Use feeding tongs only to place food, never to tease or grab the animal. Appetite may reduce before a moult, but prolonged refusal accompanied by poor posture, rapid movement at the surface or abnormal water results needs investigation. A hungry crayfish may become more destructive, yet overfeeding is not a safe way to prevent predation.

Behaviour and daily activity

Expect a bottom-oriented animal that explores by touch and smell. Some individuals are visible throughout the day; others wait until the room quietens or the aquarium lights dim. Carrying food, moving loose substrate, defending a cave, standing at the entrance with raised claws and testing climbing routes can all be normal.

Normal territorial display should not be confused with proof that cohabitation is safe. A crayfish that ignores a fish for weeks may still catch it while it rests near the substrate. Likewise, an animal that shares a cave area as a juvenile may become intolerant after growth or a moult. Behaviour is individual and can change.

Provide enrichment through a complex but stable layout: more than one tunnel, safe wood, shaded cover, open feeding space and varied surfaces. Avoid constant redecorating. The animal establishes familiar routes and retreats, and repeated disruption can leave it exposed during a vulnerable stage.

Compatibility and the species-first plan

The lowest-risk arrangement is one Red Claw Crayfish in its own properly sized aquarium. It is not shrimp safe, not reliably snail safe, not reliably plant safe and not guaranteed safe with fish. Claws, night activity and opportunistic feeding mean that peaceful behaviour observed during the day cannot remove the risk.

Small bottom fish, corydoras, loaches, small plecos, slow fish, long-finned fish and sleeping livebearers are particularly exposed. Fast midwater fish are sometimes kept with large crayfish in spacious aquariums, but that remains a risk decision rather than a recommendation or guarantee. Make sure every companion also matches the warm, neutral-to-alkaline water.

Keeping two crayfish together carries risks during territorial disputes and moulting. A larger aquarium, many separated shelters and broken lines of sight reduce but do not remove those risks. Never buy two juveniles on the assumption that they will become a compatible pair. Maintain an immediately usable separate aquarium or divider if cohabitation is attempted.

Plants, substrate and display design

Red Claw Crayfish can dig, clip shoots and uproot plants. Hardy epiphytes attached securely to wood or rock may survive better than delicate stems or carpeting plants, but no plant is guaranteed safe. The beginner live-plant guide can help compare robust plant types, provided the layout accepts that this animal may redesign it.

Sand or smooth gravel is easier on the underside than sharp substrate and allows natural digging. Keep the bed shallow beneath heavy structures so the crayfish cannot excavate a collapse. Dark wood, pale sand and shaded caves can make blue and bronze tones easier to see, but visual contrast should never take priority over stable furnishings.

Use aquarium-safe materials only. Avoid copper ornaments, exposed metal, painted items not intended for aquariums and shells collected from unknown environments. Rinse new decor without detergent and check that every opening remains usable after the crayfish gains body width.

Selecting the live size and sale unit

The product selector shows the live sizes currently offered. A 4-5 cm animal may be less imposing on arrival, while a 5-7 cm animal is further into juvenile growth. Neither option is a different species, colour guarantee or adult-size class. Select by the aquarium's readiness and your experience, not by the hope that the smaller size will remain small.

Each quantity is one unsexed live crayfish at approximately the chosen size. Natural variation is expected because length, claw proportion and colour cannot be standardised like a manufactured object. Multiple quantities do not guarantee a pair, a compatible group or a chosen sex ratio. Do not order more than one unless the adult enclosure and separation plan already exist.

Arrival and acclimation

Prepare the aquarium before delivery: mature filter, tested water, secure lid, protected heater, stable caves and low lighting. Read the current live-animal delivery and guarantee information before selecting a date. Be present to receive the parcel and follow the instructions supplied with the order, because travel conditions and the receiving aquarium both affect the safest acclimation method.

Do not open the transport bag and leave it standing for a long period. Match temperature as directed, introduce the animal carefully without adding transport water to the aquarium, and release it beside a prepared shelter. Never lift a crayfish by a claw or leg. If it must be guided, use a suitable container and keep hands away from the claws.

Keep lighting low and disturbance minimal for the rest of the day. A new arrival may hide, refuse the first meal or appear duller than the gallery. Offer a small sinking food once it has settled, then remove leftovers. If there is a delivery concern, use the guarantee process promptly and preserve the packaging and requested evidence.

Routine maintenance

Observe the crayfish daily and remove obvious uneaten food. Check that filter flow and surface movement remain strong, the lid is seated correctly and no cable opening has widened. Count limbs without chasing the animal; a missing limb may regenerate over later moults, but the cause should still be investigated.

Use regular partial water changes with dechlorinated replacement water reasonably matched for temperature and chemistry. Vacuum accessible debris without dismantling every shelter. Rinse mechanical media when flow falls, using removed aquarium water where practical, and never replace all mature biological media at once.

Record temperature, pH, GH, KH, ammonia, nitrite and nitrate often enough to see trends. A stable log is more informative than one isolated test after a problem appears. Check the aquarium more frequently during hot weather, after a moult, after equipment changes and after any period of reduced appetite.

Health and warning signs

A healthy settled crayfish should react to its surroundings, use shelters, maintain a firm shell between moults and show interest in food according to its normal rhythm. Hiding before and after a moult can be normal. Diagnose the environment before assuming every quiet period is disease.

Warning signs include repeated escape attempts, prolonged surface climbing, persistent weakness, loss of balance, foul-smelling water, a shell that stays soft, repeated failed moults, unusual lesions or continued refusal to eat outside a likely moult window. Test ammonia, nitrite, temperature, pH and oxygen conditions immediately and inspect equipment.

Crustaceans can be sensitive to treatments used routinely for fish, particularly copper-containing medicines. Never dose the main aquarium without confirming that the exact product and concentration are appropriate for crayfish. When a diagnosis or treatment is uncertain, seek advice from an aquatic veterinarian or a keeper experienced with large Cherax.

Breeding and sexing notes

Mature males usually develop the characteristic red patch on the outer margin of the large claw and may become heavier-clawed. Females can have a broader abdomen, but reliable sexing uses the position of reproductive openings on the underside, not colour alone. Juvenile proportions can be misleading.

Breeding is not a suitable beginner project. Adults can be territorial, females carrying eggs need security, and large numbers of juveniles need space, filtration and responsible homes. Never breed or distribute non-native crayfish without understanding the legal and welfare obligations that apply where you live.

This listing is for an unsexed individual. Ordering two does not create a guaranteed male-female pair and may create an immediate territorial problem. Buy for the value of one well-kept animal, not on an assumption that reproduction will follow.

Is this crayfish right for your aquarium?

Choose Red Claw Crayfish if you enjoy observing natural crustacean behaviour and can provide a secure, warm, mineral-supportive aquarium with substantial floor area. It rewards careful planning with bold movement, feeding interaction and fascinating moulting behaviour.

Choose a different animal if your priority is a delicate planted aquascape, dwarf shrimp colony, peaceful bottom-fish community or open-top display. It is also a poor choice when the adult tank is only an intention, the source water is very soft and acidic with no stable adjustment plan, or nobody can receive live delivery promptly.

Evidence used for this care guide

Legal wording and the England-and-Wales scope were checked against the current GOV.UK non-native fish, lobster and crayfish guidance and the Cefas Fish Health Inspectorate overview. Native range, pH, temperature-production context, oxygen and mineral notes were checked against the Queensland Government redclaw profile.

Colour, sexual dimorphism and exceptional adult size were cross-checked with Aquarium Glaser's specialist species account. Diet wording is deliberately broad and is supported by a peer-reviewed redclaw nutrition study indexed by PubMed. Practical tank volume, frontage and species-first recommendations are cautious husbandry judgements built from adult size, waste and territorial floor use; they are not presented as official legal minima or measurements from a field study.

Red Claw Blue Lobster FAQs

Is a Red Claw Blue Lobster really a lobster?

No. Cherax quadricarinatus is a freshwater crayfish. Blue Lobster is a common aquarium-trade name, but care must account for crayfish claws, moulting, digging and escape behaviour.

What is the scientific name?

The scientific name is Cherax quadricarinatus. Recording that name is important because common names are inconsistent and the legal status of other crayfish species can differ.

How large does it grow?

Plan for a substantial adult of roughly 18-20 cm. Exceptional mature males can approach 30 cm, although that is not the expected size of every individual.

What aquarium size does one adult need?

Our cautious practical recommendation is at least 120 litres with around 90 cm or more of frontage; 180 litres or more is preferred. Floor area matters more than height.

What temperature should I use?

Keep a stable 22-26 C as the core aquarium range. Avoid cold rooms, sudden water-change shifts and summer overheating, and maintain good oxygenation.

What pH and hardness are suitable?

Aim for pH 7.0-8.5 and approximately 5-22 dGH. Stable neutral-to-alkaline, mineral-supportive water is preferable to soft acidic conditions that can hinder shell hardening.

Does the aquarium need a lid?

Yes. Use a close-fitting lid and cover openings around filters, airline and cables. Crayfish are strong climbers and can use equipment as an escape route.

Can Red Claw Crayfish live with fish?

No fish is guaranteed safe. Fast midwater fish are sometimes attempted in a large aquarium, but sleeping, slow and bottom-dwelling fish can be caught. A species-first setup is safer.

Can it live with shrimp or snails?

Treat dwarf shrimp and small snails as prey. Do not choose this species for a shrimp colony or expect invertebrate companions to remain safe.

Will it damage aquarium plants?

It can dig, cut and uproot plants. Hardy plants secured to wood or rock may last better, but even those are not guaranteed to remain untouched.

What does it eat?

Use a varied omnivorous diet based on sinking crustacean food, plant-rich foods, safe vegetables, leaf litter and occasional measured protein foods. Remove leftovers promptly.

Why is my crayfish hiding and not eating?

A new arrival or an animal preparing to moult may hide and eat less. Check water and equipment, keep the shelter quiet and investigate if weakness or refusal continues beyond a likely moult period.

Should I remove the shed shell?

Usually leave it temporarily if water quality remains good. The crayfish may eat much of the shell and recover minerals; remove only deteriorating leftovers as needed.

Can I choose a male or female?

No. The animals are sold unsexed, especially at juvenile size. A visible red claw patch generally develops in mature males and may not be clear when young.

Will mine look exactly like the gallery images?

No. The gallery is representative. Colour and proportions vary with the individual, age, lighting, background and moult stage, and the exact photographed animal is not promised.

Is Red Claw Crayfish legal to keep in the UK?

Current GOV.UK guidance permits Cherax quadricarinatus without a licence in an indoor ornamental aquarium in England and Wales. Rules elsewhere in the UK must be checked with the relevant national authority.

What should I do if I can no longer keep it?

Contact an experienced aquatic keeper or retailer to arrange secure rehoming. Never release the animal into any pond, river, canal, drain or other outdoor water. For order-specific help, use our contact page.

For help with an order or the live-delivery process, please contact Tropical Fish Co.