Cherax boesemani

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Cherax boesemani, also known as the Black Scorpion Crayfish, is a freshwater crayfish from western New Guinea, Indonesia. This species is distinguished by its dark coloration, strong claws, and impressive appearance. It remains uncommon in the aquarium trade, making it a sought-after invertebrate among specialized keepers. Like several crayfish in the genus Cherax, it requires a well-structured aquarium, stable water, and numerous hiding places. Its mainly crepuscular and territorial behavior should also be considered before purchase. A secure setup and careful selection of tank mates are important for long-term success.

General species description

Cherax boesemani is a freshwater crayfish belonging to the Parastacidae family. It is mainly benthic and becomes more active at dusk or during the night. Its sturdy body, powerful claws, and tendency to explore the layout make it a highly visible animal in a suitable aquarium. Despite its imposing appearance, it is not a specialized predator: it mainly feeds on available bottom foods and may capture slow or opportunistic prey. It can defend a hiding place from other crayfish, especially in a confined aquarium. Maintenance therefore requires a spacious, secure aquarium with separate shelters. This species is generally regarded as uncommon to occasional in the aquarium trade rather than a routinely available crayfish.

Geographical origin and biotope

Country of reference: Indonesia. Cherax boesemani is associated with the Ayamaru lake system in the Doberai Peninsula of West Papua, on the island of New Guinea. Its natural habitat consists of freshwater shoreline areas where it can shelter among stones, roots, plant debris, and crevices. The margins of these lakes are influenced by a tropical climate, with dense riparian vegetation and leaf accumulation in some areas. In an aquarium, it is better to reproduce this structure rather than create an open layout: the bottom should provide passages, cavities, and shelters of different sizes. Efficient filtration, well-oxygenated water, and stable water chemistry are important. The shallow shoreline areas are particularly useful as inspiration for the aquarium design.

Precise location and local name

The known range of Cherax boesemani is centered around the Ayamaru Lakes in the Sorong region of West Papua, Indonesia. This island distribution gives the species biogeographical interest, as it is associated with a distinct freshwater area rather than a broad continental range. The English trade name Black Scorpion Crayfish refers to its dark coloration and claws, which resemble those of a scorpion. This remains the most widely used common name in the international aquarium trade, while an Indigenous local name is not used consistently in commerce. For aquarists, scientific identification remains important because several dark Cherax may be sold under broad commercial labels. The Ayamaru origin should be retained in records and stock lists for proper traceability.

Appearance and physical characteristics

Cherax boesemani has a compact, heavily armored body with a broad cephalothorax, segmented abdomen, and long antennae. Its coloration ranges from very dark brown to bluish black, sometimes with lighter shades around the joints or along the claw margins. The powerful claws are among its most visible features and are used for defense, feeding, and territorial interactions. As with other crayfish, the shell is periodically replaced during molting; the animal is vulnerable at this time and must be able to retreat into a shelter. The commonly stated maximum aquarium size is about 15 cm, including the claws and abdomen. Color may vary with age, stress, lighting, substrate, and water conditions.

General diet

Cherax boesemani is an omnivorous and opportunistic crayfish. Its diet should combine crustacean pellets or tablets, plant foods, and small portions of protein-rich foods. Zucchini, spinach, peas, or suitable leaves may supplement the diet, while meaty or frozen foods can be offered sparingly. Dried leaves from safe, untreated species provide both fiber and a grazing surface. Uneaten food should be removed to protect water quality. A varied diet supports regular molting, but overfeeding quickly increases organic waste. Portions should therefore remain moderate and varied, with particular attention to available calcium from the water and food to support new shell formation.

Essential data

• Name of the river of origin: Ayamaru lake system
• Local name used: Black Scorpion Crayfish
• Origin of the scientific name: The genus Cherax and an epithet dedicated to Marinus Boeseman
• Full-name etymology: Cherax is an ancient Greek name associated with crayfish; boesemani honors Marinus Boeseman
• Common or vernacular names: Black Scorpion Crayfish; black scorpion crayfish
• Family: Parastacidae
• Subfamily: Astacopsinae
• Pronunciation: keh-raks - boh-eh-seh-MAH-nee
• Discovery: Holthuis, 1949
• Maximum adult size: About 15 cm
• Water temperature and pH: 22 to 28 °C; pH 6.5 to 8.0
• Appearance of the watercourse and surrounding vegetation: Tropical lake shorelines with stones, roots, leaves, and dense riparian vegetation
• Typical tank mates: Peaceful midwater fish of suitable size; avoid small invertebrates and long-finned fish
• Temperament and behavior: Mainly crepuscular, territorial around shelters, and sometimes aggressive toward other crayfish
• Water depth: Shallow shoreline areas
• Sexual dimorphism: Adult males generally have more developed claws; females have a broader abdomen for carrying eggs
• Bottom structure and flow: Bottom made of stones, sand, plant debris, and shelters; calm to gently flowing water

In your aquarium

To maintain Cherax boesemani successfully, provide an aquarium with enough floor space for several hiding places. A tightly fitting lid is recommended because crayfish can climb along equipment and tubing. Keep the water clean, stable, and well oxygenated, and remove leftover food promptly. Tank mates must be selected carefully: small, slow fish, shrimp, and snails may be caught. Extra attention is needed during molting, along with a varied diet and a structured layout. These are the keys to long-term care. Meeting these needs reduces stress, limits territorial conflict, and gives the crayfish a safer environment in which to feed, shelter, and molt.