Arrow Crab

Arrow Crab (Stenorhynchus seticornis) is native to Indo-Pacific reef ecosystems, with wild populations distributed across coral reefs, sandy lagoons, and rocky tide pools. Captive specimens are typically wild-collected; some species are starting to be aquacultured but most Arrow Crab sold today still comes from wild reef collection. Sustainable sourcing matters - look for vendors who can verify their collection practices, and consider aquacultured alternatives when available.

Arrow Crab requires a minimum of 30 gallons for healthy adults. The minimum is based on the species' adult size (6 inches (legs)), territorial range, and behavior pattern. Most Arrow Crab sold at small juvenile size will reach full adult size within 12-24 months and the system must be sized to the adult, not the juvenile.

For a Arrow Crab setup: mature reef tank with stable parameters, live rock for cover, sandbed substrate (1-2"), reef-grade lighting if photosynthetic, and a fully-cycled biological filter at least 6 weeks old. Newly-cycled tanks under 6 weeks crash the parameters that Arrow Crab depends on.

Browse our 30-gallon aquarium guide for the complete equipment list.

Arrow Crab requires standard reef parameters held tightly stable:
Temperature: 76-80°F (24-27°C)
Specific gravity: 1.025 (refractometer-measured)
pH: 8.1-8.4
Alkalinity: 8-9 dKH
Calcium: 420-450 ppm
Magnesium: 1300-1400 ppm
Ammonia + nitrite: Both 0 ppm
Nitrate: Under 10 ppm
Copper: 0 (lethal to invertebrates)

Arrow Crab is sensitive to copper - never medicate the display tank with copper if Arrow Crab is present. Stable parameters beat perfect parameters.

Arrow Crab is a carnivore. Eats meaty foods - frozen mysis shrimp, brine shrimp, finely chopped seafood, and quality carnivore pellets. Live food (PE Mysis, live brine, live blackworms) triggers feeding response in stressed or new arrivals. Feed 2-3 times weekly for adults; daily for growing juveniles. Feed Arrow Crab appropriately for its size + activity level. Overfeeding is the #1 cause of water-quality crashes in tanks of all sizes.

Arrow Crab is generally peaceful and compatible with most reef community species. Avoid keeping with predatory fish that view inverts as food: large wrasses (especially halichoeres + thalassoma), triggerfish, pufferfish, and certain large angelfish. Multiple Arrow Crab can share a tank but compete for food.

Browse care guides for tankmate-compatibility tables for Arrow Crab and similar species.

Arrow Crab reaches 6 inches (legs) at adulthood with a captive lifespan of 5-8 years with proper care. Many marine inverts molt periodically; provide adequate calcium and a stable parameter regime to support healthy molts.

Arrow Crab breeding in captivity ranges from straightforward (some shrimp, snails) to nearly impossible (most starfish, urchins) due to pelagic larval requirements. Captive-bred specimens are increasingly available from sustainable aquaculture facilities; check with vendors before assuming wild-caught origin.

Arrow Crab is sensitive to copper, ammonia spikes, low oxygen, and rapid parameter swings. NEVER use copper medications in a tank with Arrow Crab. Symptoms of stress: reclusive behavior, color loss, refusal to feed, abnormal molting (incomplete or stuck molts). Most Arrow Crab deaths trace back to acclimation shock or parameter mismatch - drip-acclimate over 45-60 minutes when adding to a new tank.

Arrow Crab is sold at LFS (local fish stores), online retailers, and direct from breeders/wholesalers. Pricing varies widely by source, size, and quality:

Budget tier: $15-60
Mid-tier: $30-150
Premium tier: $100-500

Browse live Arrow Crab from vetted Fast Aquatics vendors with carrier-tracked overnight shipping (FedEx Priority + UPS Next Day), climate-aware hold logic, and a 4-hour DOA window with photo-evidence claims. Captive-bred or aquacultured specimens cost more upfront but arrive healthier and integrate faster.

How big does Arrow Crab get?

6 inches (legs) at adulthood within 12-24 months.

How long does Arrow Crab live?

5-8 years with proper care.

What is the minimum tank/pond size?

30 gallons, with larger systems strongly recommended.

Is Arrow Crab hard to keep?

Arrow Crab is rated intermediate difficulty.

What does Arrow Crab eat?

Arrow Crab is a carnivore; appropriate diet matches its natural feeding pattern.

Where can I buy Arrow Crab?

Browse live Arrow Crab from vetted Fast Aquatics vendors with carrier-tracked Buyer Protection and a 4-hour DOA window.

How much does Arrow Crab cost?

$15-500 depending on source and quality.

Do I need to quarantine Arrow Crab?

Yes - quarantine new Arrow Crab for 4-6 weeks in a separate tank before adding to your display.

Is Arrow Crab reef safe?

Generally yes - Arrow Crab is reef-safe and suitable for established reef tanks.