Arrowhead Crab (Stenorhynchus seticornis / Arrow Crab)
The Arrowhead Crab, also known as the Arrow Crab, is a fascinating marine invertebrate recognised for its triangular body, extremely long legs, and elongated pointed rostrum. An active scavenger and opportunistic predator, it is often added to marine aquariums to help control nuisance bristleworms while providing plenty of character.
Compatibility:
Generally peaceful but opportunistic. Suitable with most community marine fish, though it may prey on very small fish, feather duster worms, and ornamental shrimp if the opportunity arises. Best kept singly unless the aquarium is very large.
Reef Compatibility:
Reef-safe with caution. Safe with corals but may consume feather dusters, small crustaceans, and other sessile or mobile invertebrates. Behaviour varies between individuals.
Diet:
Omnivore – feeds on bristleworms, detritus, uneaten food, small crustaceans, and other organic matter. Supplement with mysis shrimp, chopped seafood, marine pellets, and algae-based foods as required.
Water Parameters:
- Temperature: 24–27°C
- Salinity: 1.023–1.026 SG
- pH: 8.1–8.4
- Minimum Tank Size: 100L
Care Level:
Easy – hardy and adaptable, provided water quality remains stable and plenty of hiding places are available.
Top Tip:
Arrowhead Crabs are excellent scavengers and can help reduce populations of nuisance bristleworms. Ensure they receive supplemental feeding, as hungry individuals are more likely to prey on desirable invertebrates.
