Moderate
Thai Micro Spider Crab (Limnopilos naiyanetri) - Aquarium Crabs
22–28°C · pH 6.5–7.5 · 20L
£6.99
Red Claw Blue Lobster (Cherax quadricarinatus), a bold blue freshwater crayfish for secure, mature aquariums with hard water, strong filtration and specialist tank planning.
Cherax quadricarinatus
Red Claw Blue Lobster (Cherax quadricarinatus), a bold blue freshwater crayfish for secure, mature aquariums with hard water, strong filtration and specialist tank planning.
Maintain these water conditions for optimal health and vibrant colors
Red Claw Blue Lobster, Cherax quadricarinatus, is a large Australian freshwater crayfish with blue, green and bronze tones and the red claw marking that mature males are known for. It is also sold in the hobby as blue lobster crayfish, redclaw crayfish, Australian red claw crayfish or blue Cherax. Those names can make it sound like a simple community animal, but it is best treated as a specialist aquarium crustacean: hardy once settled, active, very strong, and much better in a secure species-led setup than in a casual mixed fish tank.
This listing covers Petra Aqua stock under SKU K498, with 4-5 cm and 5-7 cm size options on the same Shopify product. The first image is the exact Petra source photo for this product group, added so the page has a supplier-backed reference alongside the existing aquarium scene images. Juveniles can show brighter blue than older animals; adults often deepen in colour and become heavier-bodied as they mature.
If you are buying a redclaw crayfish online, plan the adult aquarium before purchase. Cherax quadricarinatus can become a substantial animal, and Aquarium Glaser notes that males can reach up to around 30 cm in exceptional cases. Most home aquarium specimens are kept for their colour and behaviour rather than their final size, but the care plan still needs floor space, caves, mineral support and a lid that leaves no escape gaps.
The old version of this page pushed too many search phrases into the care text and even described the animal like a general tropical fish listing. This refresh keeps the useful buyer terms, but uses them where they make sense: in the title, search snippet, quick facts and genuine care explanation. The result is clearer for shoppers, cleaner for Google, and more useful for AI assistants that need to understand whether this is a fish, a shrimp, a crab or a crayfish.
Redclaw crayfish come from warm northern Australian freshwater habitats. Business Queensland describes the species as native to tropical Queensland and the Northern Territory, with natural habitat including billabongs and pond-like waters. In an aquarium this translates into a bottom-focused animal that explores, digs, grazes, rearranges loose decor and spends a lot of time around shelters.
Unlike many ornamental fish, a crayfish interacts physically with the tank. It can climb airline tubing, push against loose lids, pull at plants and test gaps around filter pipes. A beautiful aquascape can be damaged quickly if it is not designed around a crayfish. Use heavier decor, stable rockwork, wood that cannot roll, and caves that the animal can enter without becoming trapped after a moult.
Moulting is the key care event. A crayfish grows by shedding its old shell, then hardening a new one. During that soft-shell period it is vulnerable, easily stressed and more likely to hide. Provide several shelters and avoid moving decor around the animal. Leave the moult in the aquarium for a while unless water quality demands removal, because crayfish often re-eat part of the shell to reclaim minerals.
Expect a confident animal once it settles. Some individuals are visible during the day, while others become active after lights dim. Rearranging small stones, dragging food into a hide, testing the glass corners and defending a favourite cave are normal behaviours. Sudden lethargy, failed moults, repeated climbing attempts or refusal to use shelters can point to stress, poor water quality, unsuitable tank mates or unstable temperature.
For young 4-7 cm animals, a smaller grow-on tank can work temporarily, but long-term care should be planned around adult strength and territory. A 90 litre tank is a practical starting point for one juvenile, while 120 litres or more gives better stability and floor area for an adult. Footprint matters more than height. A long aquarium with caves at both ends is more useful than a tall display with limited bottom space.
A tight lid is not optional. Crayfish are capable climbers and can leave the water if pipework, cables or decor gives them a route upwards. Cover every gap around filters, heaters and cable exits. Keep the waterline slightly below the rim and check the lid after maintenance. Escapes are one of the avoidable risks with large freshwater crayfish.
Use strong filtration and steady oxygenation. These animals are messy compared with small fish and shrimp, and uneaten food can spoil quickly. A mature biological filter, regular testing, and sensible feeding matter more than chasing a perfect ornamental layout. Sand or smooth gravel, robust caves, wood, stones and open floor space make a better home than delicate carpeting plants.
Decor should create broken lines of sight. A single central cave can become a trap or a territory trigger, especially if you try more than one crayfish. Better layouts include several hides, at least one shaded retreat, some open feeding space and enough clearance for the animal to turn without scraping its shell. Secure any heavy rocks directly on the tank base before adding substrate, so digging cannot undermine them.
Redclaw crayfish are robust when conditions are stable, but they should not be treated as disposable clean-up animals. Business Queensland gives optimal growth around 26-29 deg C and notes that pH below 7 or low calcium can affect shell hardening. For aquariums, a warm stable range around 23-29 deg C, pH 7.0-8.5 and moderate to hard mineral content is a sensible target.
Do not keep this species cold. FAO aquaculture notes describe Cherax quadricarinatus as a warm-water species with reproduction above 23 deg C, and Business Queensland notes deaths at cold and hot extremes in production conditions. In a home aquarium, the safer approach is consistency: avoid cold rooms, avoid summer overheating, and match water-change temperature carefully.
Minerals are especially important after moulting. Keep carbonate hardness and general hardness from falling too low, and feed a varied diet with mineral-rich foods. If you keep very soft-water fish elsewhere, do not assume the same water is ideal here. This species does better in water that supports shell formation.
Test ammonia and nitrite at zero, and keep nitrate under control with regular maintenance. Large crayfish produce more waste than their purchase size suggests, so new tanks should be fully cycled before introduction. If the aquarium has been running only a few days, wait. A mature filter and stable mineral profile are worth far more than rushing the order.
Cherax quadricarinatus is an opportunistic omnivore. Offer quality sinking pellets or crustacean sticks as the staple, then rotate algae wafers, blanched vegetables, leaf litter, small pieces of fish-safe frozen food and occasional protein feeds. Remove leftovers before they foul the water. A hungry crayfish is more likely to damage plants or harass tank mates, but overfeeding creates water-quality problems just as quickly.
Feed after lights dim if the animal is shy. Many crayfish become bolder once settled and will come out for food, but a new arrival may hide through the first few days. Avoid copper-based medications and treatments unless a product is explicitly safe for crustaceans. Crayfish, shrimp and snails are all more sensitive to some treatments than most fish.
Vegetable matter is useful, but do not rely on soft vegetables alone. A varied diet supports growth, colour and moulting. Good options include sinking invertebrate foods, algae wafers, small pieces of courgette, spinach or peas, Indian almond leaves, and occasional frozen foods offered sparingly. Remove soft foods the same day if they are not eaten.
The honest answer is that a species-first crayfish aquarium is safest. Red Claw Blue Lobsters are not reliable with dwarf shrimp, small bottom fish, slow fish, fancy long-finned fish or delicate planted layouts. They may catch resting fish at night, nip fins, eat shrimp, uproot plants or claim caves from other bottom dwellers.
If you try tank mates, choose robust, fast mid-water fish in a larger aquarium and accept that risk remains. Avoid corydoras, loaches, small plecos, dwarf cichlids, bettas, guppies, shrimp and snails you would be upset to lose. Do not keep multiple crayfish together unless the aquarium is large, heavily structured and you are ready to separate animals if conflict appears.
Two size options are listed because Petra supplies different juvenile sizes under the same source image. The larger option may settle more boldly and needs the same adult planning as the smaller option. Do not buy two just because they are small today. If you want a pair or group, prepare a larger enclosure with redundant shelters and a backup tank.
Red Claw Blue Lobsters can look outstanding in a display aquarium, but the display must be built around their behaviour. Hardy epiphyte plants attached to wood or rock may last better than stem plants rooted in the substrate. Even then, damage is possible. If your goal is a pristine aquascape, choose shrimp or small peaceful fish instead.
For a crayfish display, focus on contrast: dark wood, pale sand, mineral-rich stones and open viewing areas make the blue and bronze colours easier to see. The animal will often carry food, stand at a cave entrance, climb low wood and patrol the front glass once it learns the feeding routine. That activity is the appeal of the species, but it is also why escape-proof design matters.
Your Red Claw Blue Lobster should be acclimated slowly. Float the sealed bag to match temperature, then gradually mix small amounts of aquarium water over 45-60 minutes. Net the crayfish into the tank rather than pouring bag water in, keep lights low, and let it find cover. Do not handle it or chase it around the aquarium on arrival.
UK orders are supported by our Live Arrival Guarantee when the delivery terms are followed. First-time customers can use WELCOME10 where eligible at checkout. Those trust signals belong in the buying section and SERP snippet, so they are included naturally here without forcing discount language through the care guide.
Before delivery day, check that the lid is ready, the heater guard is secure, and the caves are already in place. If the animal arrives close to a moult, it may hide immediately. That is normal. Keep the lights low, offer a small sinking food once settled, and avoid major water changes for the first day unless testing shows a problem.
Never release aquarium crayfish into ponds, rivers, canals or outdoor drains. Aquarium Glaser specifically warns that Cherax quadricarinatus has invasive-risk concerns in Europe, and responsible keepers should treat every non-native crayfish as a secure indoor animal. If you can no longer keep it, contact an aquatics shop, rescue network or experienced keeper rather than releasing it.
Choose this species if you want a bold, fascinating crustacean and you are prepared to build the aquarium around its needs. It is a poor impulse buy for a peaceful community tank, but in the right secure setup it can be a memorable centrepiece with real personality.
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