{"id":1122,"date":"2026-02-16T22:39:24","date_gmt":"2026-02-16T22:39:24","guid":{"rendered":"https:\/\/aquadistribution.co.uk\/product\/arrowhead-crab-stenorhynchus-seticornis\/"},"modified":"2026-02-16T22:39:25","modified_gmt":"2026-02-16T22:39:25","slug":"arrowhead-crab-stenorhynchus-seticornis","status":"publish","type":"product","link":"https:\/\/aquadistribution.co.uk\/?product=arrowhead-crab-stenorhynchus-seticornis","title":{"rendered":"Arrowhead Crab Stenorhynchus Seticornis"},"content":{"rendered":"

Arrowhead Crab (Stenorhynchus seticornis)<\/strong><\/h2>\n

(Also known as Spider Crab, Coral Guard Crab, or Arrow Crab)<\/em><\/p>\n

Overview<\/strong><\/h3>\n

The Arrowhead Crab (Stenorhynchus seticornis<\/em>) is a striking and unusual marine invertebrate<\/strong> known for its long, spindly legs<\/strong> and distinctive triangular, arrow-shaped carapace<\/strong>. Its intricate, spider-like appearance and inquisitive behaviour make it a fascinating addition to marine aquariums. Typically bronze, brown, or gold with bright white or blue markings, the Arrowhead Crab is hardy and highly active \u2014 spending much of its time perched among live rock or coral branches, scavenging for leftover food, detritus, and small invertebrates. While useful as a cleaner, it can display territorial or opportunistic behaviour, so careful tankmate selection is essential.<\/p>\n

Origin<\/strong><\/h3>\n

Native to the Caribbean Sea<\/strong>, Gulf of Mexico<\/strong>, and Western Atlantic Ocean<\/strong>. Found on coral reefs, rocky ledges, and seagrass beds<\/strong>, often hiding in crevices during the day and emerging at night to forage.<\/p>\n

Feeding<\/strong><\/h3>\n

An omnivorous scavenger<\/strong>, the Arrowhead Crab feeds on leftover food, small invertebrates, and detritus. In captivity, it will adapt readily to a varied diet. Feed 3\u20134 times per week<\/strong> with:<\/p>\n

    \n
  • \n

    Mysis shrimp or finely chopped seafood<\/p>\n<\/li>\n

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    Sinking pellets or algae wafers<\/p>\n<\/li>\n

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    Dried seaweed (nori)<\/p>\n<\/li>\n

  • \n

    Occasional meaty treats such as clam or krill<\/p>\n<\/li>\n<\/ul>\n

    While they are efficient cleaners, supplemental feeding helps prevent predatory behaviour toward tankmates or beneficial microfauna.<\/p>\n

    Lighting<\/strong><\/h3>\n

    Low to moderate lighting.<\/strong> Prefers shaded or dimly lit areas of the tank, mimicking its natural reef crevice habitat. It will often rest upside down under ledges or within coral branches during the day.<\/p>\n

    Water Flow<\/strong><\/h3>\n

    Moderate, variable flow.<\/strong> Provide alternating currents that help maintain oxygenation and simulate reef movement without dislodging the crab from its perch.<\/p>\n

    Placement & Habitat Setup<\/strong><\/h3>\n
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    • \n

      Provide ample live rock<\/strong> and hiding crevices<\/strong> for shelter and foraging.<\/p>\n<\/li>\n

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      Secure coral or rock structures \u2014 their long legs allow them to climb and explore.<\/p>\n<\/li>\n

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      Avoid coarse or sharp rockwork that could injure delicate limbs.<\/p>\n<\/li>\n<\/ul>\n

      Tank Mates<\/strong><\/h3>\n

      Semi-aggressive \/ reef safe with caution.<\/strong> Compatible with:<\/p>\n

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      • \n

        Peaceful, medium-sized reef fish (tangs, blennies, clownfish, etc.)<\/p>\n<\/li>\n

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        Snails, urchins, and most shrimp (with observation)<\/p>\n<\/li>\n

      • \n

        Other crustaceans if sufficient space and food are available<\/p>\n<\/li>\n<\/ul>\n

        Use caution with:<\/p>\n

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        • \n

          Tiny shrimp (e.g., sexy shrimp, anemone shrimp) \u2014 may be preyed upon<\/p>\n<\/li>\n

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          Small gobies or sleeping fish \u2014 may be harassed at night<\/p>\n<\/li>\n

        • \n

          Large, aggressive fish (triggers, puffers, wrasses) that may attack the crab<\/p>\n<\/li>\n<\/ul>\n

          Aggression<\/strong><\/h3>\n

          Semi-aggressive.<\/strong> Stenorhynchus seticornis<\/em> is territorial toward other crabs and may prey on small shrimp or weakened fish if underfed. It is best kept singly and provided with regular food to curb aggression.<\/p>\n

          Experience Level<\/strong><\/h3>\n

          Intermediate.<\/strong> While hardy and adaptable, the Arrowhead Crab\u2019s opportunistic nature requires careful management and observation in mixed reef environments.<\/p>\n

          Water Parameters<\/strong><\/h3>\n
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          • \n

            Temperature:<\/strong> 24\u201327\u00b0C (75\u201381\u00b0F)<\/p>\n<\/li>\n

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            pH:<\/strong> 8.1\u20138.4<\/p>\n<\/li>\n

          • \n

            Salinity:<\/strong> 1.024\u20131.026 SG<\/p>\n<\/li>\n

          • \n

            Ammonia \/ Nitrite:<\/strong> 0 ppm<\/p>\n<\/li>\n

          • \n

            Nitrate:<\/strong> <10 ppm<\/p>\n<\/li>\n

          • \n

            Tank Size:<\/strong> Minimum 75 litres (20 gallons)<\/strong> per crab; larger tanks preferred for stability and territory<\/p>\n<\/li>\n<\/ul>\n

            Lifespan & Size<\/strong><\/h3>\n
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            • \n

              Size:<\/strong> Up to 10\u201312 cm (4\u20135 inches)<\/strong> leg span<\/p>\n<\/li>\n

            • \n

              Lifespan:<\/strong> 2\u20134 years in captivity with proper care and diet<\/p>\n<\/li>\n<\/ul>\n

              Reef Compatibility<\/strong><\/h3>\n

              Reef safe with caution.<\/strong> The Arrowhead Crab contributes to the aquarium\u2019s cleanup crew by consuming detritus and bristleworms but may occasionally nip at polyps, small shrimp, or delicate coral tissue. Best suited for fish-only<\/strong> or mixed invertebrate tanks<\/strong> with robust corals and plenty of live rock for exploration.<\/p>\n

              \n

              Interesting Fact<\/strong><\/h3>\n

              The Arrowhead Crab\u2019s elongated rostrum and long limbs allow it to reach deep into coral crevices to catch bristleworms and leftover food, making it an excellent pest-control species in moderation.<\/p>\n","protected":false},"excerpt":{"rendered":"

              Arrowhead Crab (Stenorhynchus seticornis) (Also known as Spider Crab, Coral Guard Crab, or Arrow Crab) Overview The Arrowhead Crab (Stenorhynchus seticornis) is a striking and unusual marine invertebrate known for its long, spindly legs and distinctive triangular, arrow-shaped carapace. Its intricate, spider-like appearance and inquisitive behaviour make it a fascinating addition to marine aquariums. Typically […]<\/p>\n","protected":false},"featured_media":1121,"template":"","meta":[],"product_brand":[],"product_cat":[75],"product_tag":[],"class_list":{"0":"post-1122","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-marine-crabs","8":"first","9":"instock","10":"taxable","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"group_of_quantity":0,"min_quantity":0,"max_quantity":"","exclude_order_quantity_value_rules":"no","exclude_category_quantity_rules":"no","combine_variations":"no","exclude_global_add_ons":[],"addons":[],"_links":{"self":[{"href":"https:\/\/aquadistribution.co.uk\/index.php?rest_route=\/wp\/v2\/product\/1122","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aquadistribution.co.uk\/index.php?rest_route=\/wp\/v2\/product"}],"about":[{"href":"https:\/\/aquadistribution.co.uk\/index.php?rest_route=\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/aquadistribution.co.uk\/index.php?rest_route=\/wp\/v2\/media\/1121"}],"wp:attachment":[{"href":"https:\/\/aquadistribution.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1122"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/aquadistribution.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fproduct_brand&post=1122"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/aquadistribution.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fproduct_cat&post=1122"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/aquadistribution.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fproduct_tag&post=1122"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}