Arrow Crabs Amazing Facts Recipes And Habitat

Arrow crabs are similar to spider crabs. They are named because of their body structure. Its size is varying from six inches to ten inches. Females are surprisingly smaller than male. Arrow crabs species live in different regions of the world.

The common arrow crabs are found in Caribbean and other species are buy from the 

Indo Pacific region and also from California.

These are long lived species that lived in the reef aquarium. The arrow crabs attack on shrimps and small fishes. These are adoptable feeders and feed on mushrooms and polyps. 

Arrow crab’s breeding in the aquarium is not mostly successful. Larvae are known as free swimmers and hatch into two weeks. It likes to eat meaty and flakes food.

Scientific name and other names:

The scientific name of arrow crabs is “ Stenorhynchus Seticornis “. Its other names are yellow line and arrowhead crabs. These names are given because of its arrow body shape. 



Arrow crabs seem like underwater spiders .Aquarists appreciate  these crab species because of their long legs which look like spider’s legs. Its legs are 4 to 6 inches long. 

Arrow crabs have spikes on the head that are between two eyes. The carapace is white with light tan color. Dark brown lines are also present from median to margin.

Mature arrow crab is about 3 cm long and has a long rostrum which is present into a  tapered point. 

These crabs have orange and red spotted thin legs and blue violet claws which are similar to gloves.


Arrow crabs reside mostly at the bottom, corals , pebbles , sand and rock jetties.This is one of the most variable crabs species. These crabs are extensively distributed species of the Caribbean Sea and the western Atlantic ocean along Atlantic coasts from north california.


The male crab transfers sperm packets into the females. Eggs are transferred into the female’s bottom part of the abdomen. The hatched young is known as zoea and will keep on this name during their larval stage development.

During this time they have round shaped bodies and give preference to live in open water and eating planktons. 

As they grow they start molting. Once they  molt they enter into a new phase, megalops. In this stage their body and limbs look like crabs. 

Arrow crab eggs:

Under a good environment, Arrow crabs can breed all over the year. After mating, female crabs produce larger eggs and small clutches. Female crabs carry eggs in her abdomen until they hatch within a few weeks. Additionally, every female carries about 300 to 900 eggs.

There is a significant  relation between the number of eggs and the measurement of ovigerous females.

The size of eggs increases during development as a result of water uptake.



As other species of crustaceans, the arrow crabs also shed exoskeleton so that it can grow again. It may be dangerous for beginner hobbies  but the molting process is normal.

After  molting you should leave the old shell in the aquarium so that the crab can eat it. By this process the crab gets those minerals which are necessary to modify the new skeleton. Despites this crab also takes minerals from water which is helpful to  create a new skeleton. Therefore DKH level is very necessary.

You can also feed your arrow crab with a diet which is full of calcium to ensure crab shell health and power.


Arrow crabs are carnivores and  feed on the worms, reefs of algae and other dead animals or small crustaceans. They search for food at night and hide during the daytime.

Arrow crabs also eat organic and highly protein food.

Arrow crab aquarium care:

If you want to add the arrow crabs in your aquarium you must know all the care features. Arrow crabs feel comfortable within standard water conditions with pH 8.1 to 8.4. Your water tank temperature must be 72 to 78 degrees fahrenheit. Arrow crabs care is not tough because they can live in a small tank. They are  scavengers and eat each and everything which you put in the tank.

Minimum 20 gallon tank is needed for one crab. But larger tanks are good because crabs found a lot of space for swimming. 

Difference between male and female arrow crab:

You can easily explain the difference between male and female sexes. 

  • Male has a triangular abdomen and females have a round shaped abdomen.
  • Male crabs are larger in size and have bigger claws  than female crabs
Are all arrow crabs aggressive?

Are all arrow crabs aggressive?

Yes, sometimes arrow crabs can be aggressive. Because they all are predators and can prey on small crustaceans and slow moving fish. These crabs must not be kept in the company of its same species.  

Do arrow crab legs grow back?

It is not common for these crabs to miss limbs or pincers. Often, it happens as a result of the natural molting process and injury during fighting with reef mates may also be the reason for it. Mostly the legs can regrow after molting.


As previously described, Arrow crabs may be aggressively territorial, So it’s best not to keep them with other crabs. It’s not a good plan to keep many crabs in only a single tank until you have a big tank with a lot of space for the individual crab to have their own territory. Keeping more than two creatures together may create trouble of fighting. As a result of this death can be occured.

Small fishes are seen as a food source of arrow crabs so if you have this type of species in your collection, keeping arrow crabs with them is not a good choice for you.


Stenorhynchus seticornis is available on a large scale in good stores and online from reputable dealers. So you can purchase them easily for only 15$, plus shipping cost makes them affordable for most hobbyists.


Arrow crabs are marine animals and found in Brazil and the Gulf of mexico. They are lovely creatures and easy to care for as long as they are provided with a suitable saltwater environment and diet. Arrow crabs are good creatures and are unique in qualities. They can change their colour according to their environment. This is the quality due to which marine aquarists give them more preference.

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