Cherax warsamsonicus

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Cherax warsamsonicus, also known as Red Coral, is a freshwater crayfish from western New Guinea. Its coral-red coloration, sometimes marked by darker shades on the claws and shell, makes it a sought-after species among aquarists. It remains rare in the aquarium trade and requires a well-structured aquarium with sturdy shelters and clean water. Like other Cherax, it is most active at dusk and during the night. The specimen presented here is wild-collected, so careful acclimation and close observation are especially important.

General description of the species

Cherax warsamsonicus is a freshwater decapod crustacean in the family Parastacidae, adapted to streams and rivers in western New Guinea. The species is recognized by its striking coral-red coloration and its robust body, typical of the genus Cherax. It spends much of the day hidden before exploring the bottom after dark. Its behavior may become territorial, particularly in a small aquarium or when shelter is limited. Because it is uncommon in the aquarium hobby, it is best suited to aquarists able to provide stable maintenance. Wild specimens should be acclimated gradually and monitored closely during their first weeks in captivity.

Geographical origin and biotope

Country of reference: Indonesia. The species comes from the western part of New Guinea, now within Indonesia’s Southwest Papua Province. It is associated with the basin of the Warsamson River, in the Sorong region. Its natural environment consists of forest streams and freshwater sections with regular water movement. The bottom may include gravel, stones, coarse sand and plant debris. Riparian vegetation provides shade and contributes leaves and branches that function as both indirect food sources and shelters. In the aquarium, this structure should be reproduced rather than offering an open layout with few hiding places.

Precise location and local name

Cherax warsamsonicus is associated with the Sorong region of Indonesian western New Guinea, in the area of the Warsamson River. The scientific name directly refers to this geographical origin. The trade name Red Coral is the name most commonly used by aquarists and importers. It should not be treated as a documented vernacular name used by local communities. For wild specimens, precise collection information is especially valuable because Cherax populations may vary in color and body form. A locality-based identification is therefore preferable to relying only on a commercial label.

Appearance and physical characteristics

This crayfish has a compact body, a well-developed carapace and large claws used for defense, handling food and digging. The main coloration ranges from coral red to orange-red, with darker areas sometimes visible on the joints, legs or claws. Its antennae are long and highly mobile, while the segmented abdomen allows rapid backward movement when threatened. Maximum adult size is generally reported at about 12 cm, excluding the antennae. Color intensity may vary with age, physiological condition, stress, diet and aquarium lighting.

General diet

Cherax warsamsonicus is an omnivorous and opportunistic feeder. Its diet should consist mainly of crayfish pellets or wafers, supplemented with vegetables such as zucchini, blanched spinach or suitable leaves for invertebrates. It also consumes organic debris, biofilm and small prey when available. Regular plant matter helps prevent dietary imbalance, while occasional protein supports growth and recovery after molting. Uneaten food should be removed promptly to protect water quality. Dead fish or snails should not be used as the main food source, since this may encourage predatory interactions with tank mates.

Essential data

• Name of the source river: Warsamson River
• Local name used: Red Coral, an aquarium trade name
• Origin of the scientific name: The specific name is derived from Warsamson, the presumed source river.
• Full-name etymology: Cherax is the genus name; warsamsonicus means associated with the Warsamson River.
• Common or vernacular names: Red Coral
• Family: Parastacidae
• Subfamily: Cheraxinae
• Name pronunciation: keh-raks war-sam-soh-ni-kus
• Discovery: Christoph Lukhaup, 2015
• Maximum adult size: About 12 cm
• Water temperature and pH: In aquariums, about 22 to 28 °C; pH 6.5 to 8.0.
• Stream appearance and surrounding vegetation: Shaded forest streams with stones, gravel, plant debris and dense riparian vegetation.
• Typical tank mates: Robust, non-aggressive midwater species; avoid slow fish, very small fish and vulnerable invertebrates.
• Temperament and behavior: Territorial, especially toward other crayfish; mainly crepuscular and nocturnal.
• Water depth: Shallow stream and river sections.
• Sexual dimorphism: Adult males generally have more developed claws; young specimens can be difficult to sex.
• Bottom structure and flow: Stone, gravel, coarse sand and leaf-litter bottom; low to moderate flow with good oxygenation.

In your aquarium

Success depends on a secure, spacious aquarium filled with hiding places, since Cherax warsamsonicus can climb and leave the water. Use tubes, stable rocks and driftwood to create several separate territories. Effective filtration, well-oxygenated water and regular water changes are essential, particularly for a wild-collected animal. Monitor molting and remove injured tank mates. A varied diet, a smooth substrate and stable temperature will reduce stress and support long-term care of this rare and colorful crayfish.