Cherax Quadricarinatus Redclaw Care: Australian Crayfish

The redclaw is the largest crayfish most aquarists will ever keep, and at a potential 25cm and 600g it demands tank space that catches many beginners off guard. This cherax quadricarinatus redclaw care guide from Gensou Aquascaping at 5 Everton Park lays out the realities of housing Cherax quadricarinatus, a tropical north-Australian species that thrives in warm Singapore conditions but will demolish any planted tank within a week. If you want a single impressive ornamental decapod with personality, the redclaw delivers.

Quick Facts

• Scientific name: Cherax quadricarinatus
• Adult size: 20 to 25cm, occasionally larger
• Minimum tank: 200 litres for an adult, 300 litres for a pair
• Temperature: 22 to 30°C — ideal for Singapore ambient
• Water: pH 6.5 to 8.0, GH 8 to 20, KH 4 to 12
• Lifespan: 4 to 5 years
• Diet: omnivore with strong preference for animal protein

Origin and Identification

Native to the rivers of Queensland and the Northern Territory, the redclaw takes its name from the bright red patch on the outer edge of the male’s claw. Body colour ranges from olive-green to deep blue depending on diet and genetics; selectively bred lines now include vivid blue and almost-purple variants commonly sold in Singapore. The four ridges on the carapace, which give the species its name, are the easiest field ID against other Cherax.

Tank Size and Setup

A single adult needs a footprint of at least 90 by 45cm; two animals need 120 by 45cm or more, ideally with a divider strip of slate to break sightlines. Bare-bottom or fine sand works best. Forget aquasoil — it will be excavated within hours. Provide caves, lengths of large PVC pipe, slate stacks and driftwood; redclaws love a defined territory and become aggressive without one.

The lid must be heavy and gap-free. Adults are powerful enough to push aside a glass lid and walk across the floor overnight. Filtration should be a generously sized canister or sump rated for at least 5x tank turnover.

Water Parameters and Singapore Climate

This is one of the few large crayfish ideally suited to unheated Singapore tanks. Ambient room temperatures of 27 to 29°C sit perfectly inside the breeding range. Soft PUB tap requires remineralising to GH 10 and KH 5 minimum; we usually add a small bag of crushed coral to the canister. Weekly 30 percent water changes keep nitrate under 20ppm, which redclaws appreciate despite their hardy reputation.

Feeding

Adults take sinking pellets, prawn pieces, mussel, earthworm, blanched zucchini and fallen fish. Protein two to three times a week supports growth and red colouration; vegetable matter should make up the rest to prevent fatty liver issues seen in over-fed adults. A piece of cuttlebone in the tank provides background calcium for moults.

Sexing and Breeding

Mature males show the distinctive red patch on the claw membrane; females do not. Females have a pair of gonopore openings at the base of the third pair of walking legs, males at the fifth. Breeding occurs readily at 26 to 28°C. The female carries 100 to 800 dark brown eggs under her tail for six to ten weeks, releasing fully formed 8mm juveniles. Survival in the parent tank is poor; a separate grow-out with heavy planting and brine shrimp nauplii works better.

Moulting

Adults moult every two to four months. The process takes 30 minutes and the animal is vulnerable for 48 to 72 hours afterwards. Leave the cast shell in the tank; the calcium re-ingestion is essential. Failed moults in redclaws almost always trace to insufficient hardness or a temperature crash from over-aggressive water changes.

Tank Mates and Aggression

Treat this species as solitary or as a single bonded pair. They will catch and eat any slow or bottom-dwelling fish, including plecos, corydoras and loaches. Fast mid-water schools such as silver dollars or larger tetras can survive but will lose stragglers over time. Other crayfish, even the same species, will fight unless the tank is large enough for true territory separation.

Singapore Sourcing and AVS Note

Redclaws are legally available in Singapore as ornamentals and food, sold at C328, several Pasir Ris farms, and on Carousell from $15 for juveniles up to $80 for large blue adults. As with all non-native species, AVS prohibits release into local waterways. Ponds and outdoor setups must be escape-proof. The species is established as an invasive in several countries — do not contribute to that list.

Common Problems

Most issues come down to space and water hardness. A redclaw kept in a 60-litre tank will become aggressive, refuse food and moult poorly. Soft water leads to thin shells and missing claw segments. Fungal infections at joint membranes usually clear with improved water quality and a salt dip. If your animal stops eating for more than two weeks and is not pre-moult, check ammonia and nitrate first.

Related Reading

• Cherax Destructor Yabby Care Guide
• Electric Blue Crayfish Care Guide
• Blue Crayfish Care Guide
• CPO Dwarf Crayfish Care Guide
• Marbled Crayfish Care Guide