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The Blue Moon Snakeskin, sold under the name Cherax cf. gherardii, is a freshwater crayfish sought after for its bluish coloration and reticulated pattern. The prefix “cf.” indicates an affinity with Cherax gherardii, but it does not replace a complete taxonomic identification. Native to the New Guinea region, this crayfish inhabits warm freshwater environments and is most active at dusk and during the night. Because it is offered less consistently than the most common species in the genus, it deserves a carefully arranged aquarium, many hiding places, and close attention to water quality.

General species description

Cherax cf. gherardii is a freshwater crayfish in the Parastacidae family, adapted to the tropical freshwater environments of New Guinea. It is valued in aquariums for its metallic blue coloration and pattern resembling snakeskin. Like other Cherax, it has a strong carapace, two claws, and growth marked by moulting. Its activity usually increases when the lighting becomes dim. Territorial by nature, it needs sufficient space to reduce confrontations, especially between adults. This form is collected from the wild and remains less common in the trade than the larger Australian crayfish species that are more widely distributed.

Geographical origin and biotope

Reference country: Papua New Guinea. Cherax cf. gherardii is associated with the freshwater environments of the New Guinea region, where tropical streams may pass through forested areas, vegetated banks, and habitats containing abundant plant debris. It uses shelters between stones, roots, and submerged wood. In an aquarium, reproducing this structure is preferable to creating an open layout. Stable, well-oxygenated water with little waste accumulation is better suited to its lifestyle than a heavily polluted or poorly maintained tank. Commercial availability is moderate and irregular.

Precise location and local name

The most commonly used trade name is Blue Moon Snakeskin. This name describes the animal’s appearance rather than representing a regional vernacular name. The term “snakeskin” refers to the reticulated pattern visible on the carapace and abdomen, while “Blue Moon” refers to the blue reflections shown by some specimens. Because the name includes “cf.”, specimens sold under this label may be related to Cherax gherardii without the trade name itself proving a complete identification. For proper records, it is useful to keep the origin information supplied with each shipment.

Appearance and physical characteristics

The body is segmented and protected by a hard carapace, with an articulated abdomen ending in a tail fan. Its claws are well developed and are used for defense, handling food, and territorial interactions. The most sought-after feature is a dark blue to blue-grey base colour, accompanied by darker lines or net-like markings that create the snakeskin effect. Colour intensity varies with age, moulting, lighting, stress, and surroundings. The antennae are long and sensitive. As with other crayfish, the shell must become sufficiently mineralized after every moult.

General diet

Cherax cf. gherardii is an omnivorous and opportunistic feeder. Its diet should be based on sinking crayfish pellets, supplemented with vegetables such as zucchini, spinach, or aquarium-safe leafy foods. Protein-rich foods, including frozen preparations, may be offered occasionally but should not form the basis of the diet. Fallen leaves provide plant material and encourage grazing. A varied diet supports growth and recovery after moulting. Remove uneaten food to maintain clean water, and provide an accessible source of calcium to support formation of the new shell.

Essential data

• Name of the original river:
• Local name used: Blue Moon Snakeskin
• Origin of the scientific name: Cherax is the genus name; cf. means “to compare with”; gherardii is the specific epithet.
• etymology of the full name: Cherax refers to the crayfish genus; cf. indicates a close identification; gherardii is a specific name.
• Common/vernacular names: Blue Moon Snakeskin
• Family: Parastacidae
• Subfamily:
• Name pronunciation: keh-raks sef geh-rar-dee-eye
• Discovery:
• Maximum adult size:
• Water temperature and pH: approximately 22 to 28 °C; pH around 6.5 to 8.0
• Appearance of the watercourse and surrounding vegetation: tropical freshwater, vegetated banks, roots, wood, and plant debris
• Typical tankmates: no fish is recommended as a standard tankmate; small fish, shrimp, and other crustaceans may be caught or stressed.
• Temperament and behaviour: territorial, especially toward conspecifics; mainly crepuscular and nocturnal
• Water depth:
• Sexual dimorphism: adult males generally show more visible reproductive structures at the base of the walking legs; identification requires careful handling.
• Bottom structure and flow: sand or gravel substrate with stable stones, roots, and shelters; low to moderate flow.

In your aquarium

Success depends on a spacious, covered aquarium furnished with several separate shelters. Use tubes, stable stones, and wood so each crayfish can withdraw during moulting. Efficient filtration, well-oxygenated water, and regular water changes are essential. Avoid slow fish, valuable invertebrates, and unstable decorations. Feed moderately, monitor conflicts, and remove injured individuals. With stable maintenance and a layout suited to its territorial behaviour, the Blue Moon Snakeskin can become a striking display animal, but it is not an effortless community-aquarium species.