Assuming They Are Completely Reef Safe

Arrow Crabs may prey on small shrimp, feather dusters, tiny fish, and other invertebrates as they mature.

Purchasing Them Solely for Bristle Worm Control

While they do consume bristle worms, they should not be viewed as a guaranteed solution for large infestations.

Keeping Multiple Adults in Small Aquariums

Arrow Crabs can become territorial toward one another and may fight if insufficient space is available.

Do Arrow Crabs really eat bristle worms?

Yes. Arrow Crabs are one of the most popular natural predators of bristle worms in marine aquariums. Many hobbyists add them specifically to help manage large bristle worm populations, although individual results can vary.

Are Arrow Crabs safe with Cleaner Shrimp and Blood Shrimp?

Not always. Small shrimp may be at risk, particularly as the Arrow Crab grows larger. Well-fed individuals are generally less problematic, but caution is advised when keeping them with ornamental shrimp.

Why is my Arrow Crab picking at my corals?

Arrow Crabs rarely eat healthy corals directly, but they may scavenge dying tissue, steal food from LPS corals, or irritate polyps while searching for food. Persistent picking is often a sign the crab is underfed.

Will an Arrow Crab eat Aiptasia?

Some hobbyists report occasional Aiptasia consumption, but Arrow Crabs are not considered reliable Aiptasia control animals. Peppermint Shrimp and certain filefish are typically more dependable options.

How large does an Arrow Crab get?

While their body remains relatively small, adult Arrow Crabs can develop a leg span of 15–20 cm, making them appear much larger than many hobbyists expect.

Why is my Arrow Crab always hiding during the day?

Arrow Crabs are often most active during the evening and overnight hours. Spending daylight hours hidden within rockwork is normal behaviour, particularly in brightly lit reef aquariums.

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Aquamarine Aquaristic

Arrow Crab (Stenorhynchus seticornis)

Name: Arrow Crab (Stenorhynchus seticornis)
Brand: Aquamarine Aquaristic
SKU: 47495549616374
Price: 42.0 AUD
Availability: OutOfStock

$42.00 ~~$60.00~~ Save $18 each

Out of stock

Arrow Crab (Stenorhynchus seticornis) Description The Arrow Crab is one of the most unusual-looking crustaceans available in the marine aquarium hobby. Named for its triangular body and extremely long legs,...

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Description

Arrow Crab (Stenorhynchus seticornis) Description

The Arrow Crab is one of the most unusual-looking crustaceans available in the marine aquarium hobby. Named for its triangular body and extremely long legs, this fascinating crab is a highly active scavenger that spends its time exploring rockwork and hunting for food. Arrow Crabs are particularly popular among reef keepers due to their ability to consume nuisance bristle worms and other unwanted pests. Their unique appearance, entertaining behaviour, and useful clean-up abilities make them a popular addition to marine aquariums, although their opportunistic feeding habits mean they should be kept with caution in some reef systems.

Shipping To Tasmania	NO
Shipping To Western Australia	NO

Husbandry

Care guide

Care difficulty

BeginnerModerateExpert

Beginner

Temperament

SkittishPeacefulSemi-agg.Aggressive

Semi-aggressive

Maximum size 20cm - Leg Spancm

0 cm 15 cm 30 cm

Recommended Stocking

100 Litres

Reef safe

With caution

Diet

Carnivore & Scavenger – Arrow Crabs feed on bristle worms, small crustaceans, detritus, uneaten fish food, marine flesh, and other meaty foods they encounter while foraging. In captivity they readily accept frozen mysis shrimp, krill, chopped seafood, and sinking carnivore foods. Well-fed individuals are generally less likely to target desirable tank inhabitants.

Avoid these pitfalls

Common mistakes to avoid

Learn from these common pitfalls when caring for marine livestock.

Arrow Crabs may prey on small shrimp, feather dusters, tiny fish, and other invertebrates as they mature.
While they do consume bristle worms, they should not be viewed as a guaranteed solution for large infestations.
Arrow Crabs can become territorial toward one another and may fight if insufficient space is available.

Help centre

Frequently asked questions

Find answers to common questions about our products and shipping.

Yes. Arrow Crabs are one of the most popular natural predators of bristle worms in marine aquariums. Many hobbyists add them specifically to help manage large bristle worm populations, although individual results can vary.
Not always. Small shrimp may be at risk, particularly as the Arrow Crab grows larger. Well-fed individuals are generally less problematic, but caution is advised when keeping them with ornamental shrimp.
Arrow Crabs rarely eat healthy corals directly, but they may scavenge dying tissue, steal food from LPS corals, or irritate polyps while searching for food. Persistent picking is often a sign the crab is underfed.
Some hobbyists report occasional Aiptasia consumption, but Arrow Crabs are not considered reliable Aiptasia control animals. Peppermint Shrimp and certain filefish are typically more dependable options.
While their body remains relatively small, adult Arrow Crabs can develop a leg span of 15–20 cm, making them appear much larger than many hobbyists expect.
Arrow Crabs are often most active during the evening and overnight hours. Spending daylight hours hidden within rockwork is normal behaviour, particularly in brightly lit reef aquariums.