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Sharp-femured Pistol Shrimp

Alpheus acutofemoratus

An Indo-Pacific pistol shrimp famous for its symbiotic relationship with shrimpgobies. It features a fascinating, sharp femur on its powerful snapping claw.

Taxonomy
Class:Malacostraca
Order:Decapoda
Family:Alpheidae
Genus:Alpheus
Species:Alpheus acutofemoratus

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Water Temperature

22 - 27 °C

pH Value

8.1 - 8.4

Water type

Marine

Invertebrate type

Marine shrimp

Adult size

4.5 cm

Minimum group

>= 1

KH

8 - 12 dKH

Ecological role

Symbiont

Species description

Geographical Origin and Habitat: Widespread throughout the warm waters of the tropical Indo-Pacific region. It inhabits sheltered sandy and detrital sea beds close to coral reefs, typically occupying shallow lagoons, calm bays, and intertidal flats rich in mixed sediments, shell fragments, and small gravel suitable for constructing underground burrows.
Taxonomy: A member of the Alpheidae family under the genus Alpheus. Commonly known as the Sharp-femured Pistol Shrimp due to a distinct sharp spine located on the femur of its dominant claw. Adults grow to a maximum length of 4 to 4.5 centimeters. It features a highly specialized, asymmetric snapping claw.
Social Behavior: An industrious burrower that works continuously to excavate and reinforce tunnel systems under the sand. It forms a fascinating symbiotic relationship with shrimpgobies (Gobiidae, such as Amblyeleotris or Cryptocentrus): the goby acts as an early warning sentinel using its vision, while the shrimp builds the home.
Coloration and Sexual Dimorphism: The coloration displays shades of light brown, beige, and tan, adorned with transverse bands or mottling of reddish-brown or olive green. This pattern provides excellent camouflage against sandy substrates. The walking legs can exhibit orange hues, while the massive claw has darker tips.

Care, breeding and tankmates

Tank Setup: Requires a mature marine aquarium of at least 60 liters. It is absolutely essential to provide a deep substrate of 6-10 cm (2.5-4 inches) consisting of sand mixed with small rubble, shell fragments, and gravel to allow the shrimp to construct sturdy tunnel walls. Place all heavy rocks directly on the tank glass to prevent cave-ins from digging.
Diet and Feeding: Omnivorous scavenger. They feed on organic detritus, uneaten fish food, and small benthic organisms. In captivity, they readily accept frozen foods (mysis, brine shrimp, krill) and sinking pellets or tablets. If paired with a goby, the goby will often share food by carrying pieces down into the burrow entrance.
Water Quality: Demands stable marine water parameters: temperature 22-27°C (72-81°F), pH 8.1-8.4, specific gravity 1.022-1.025. Ammonia and nitrites must be kept at zero. Proper levels of calcium, magnesium, and iodine are necessary to ensure successful molting of their chitinous exoskeleton.
Compatibility and Tankmates: Fully peaceful and 100% reef-safe. It is an excellent candidate for reef tanks. Housing it with a compatible symbiotic shrimpgoby is highly recommended to stimulate natural behaviors. Avoid predatory tankmates that feed on decapod crustaceans, such as puffers, triggerfish, hawkfish, and large wrasses.
Aquarium Breeding: Captive breeding in home aquariums is very rare and challenging. After mating inside the burrow, the female carries the fertilized eggs under her abdomen for several weeks. The larvae are released as free-floating plankton and must go through complex larval stages, requiring specialized micro-algal feeds.
Risks and Diseases: The primary risk to this invertebrate is exposure to copper-based medications or heavy metals, which are highly toxic and fatal. They are highly vulnerable during the molting process, during which they seal the burrow entrance; never attempt to excavate them or disrupt their home during this period.

Geographic Origin and Distribution

Widespread throughout the warm waters of the tropical Indo-Pacific region. It inhabits sheltered sandy and detrital sea beds close to coral reefs, typically occupying shallow lagoons, calm bays, and intertidal flats rich in mixed sediments, shell fragments, and small gravel suitable for constructing underground burrows.

Origin

Tropical oceans and reefsEast Asia

Invertebrate profile

Diet
Omnivore
The Alpheus acutofemoratus is generally considered an opportunistic omnivore that will scavenge for leftover food, detritus, and small organisms. In the home aquarium, its diet should be supplemented with a variety of meaty foods such as frozen mysis shrimp, brine shrimp, and high-quality sinking pellets. Providing a varied diet ensures they receive the necessary nutrients for growth and molting. Feeding them targeted amounts helps prevent starvation while keeping the aquarium clean.
Ecological role
Symbiont
In its natural habitat, the Alpheus acutofemoratus serves as a valuable cleaner and scavenger, helping to control detritus and organic waste. By consuming uneaten food and dead organic matter, it plays a critical role in nutrient recycling within the reef ecosystem. Some species within this group also engage in symbiotic relationships with other marine life, providing cleaning services in exchange for food. Their presence indicates a healthy and balanced marine environment.
Shock sensitivity
High
The Alpheus acutofemoratus is quite sensitive to sudden changes in water parameters such as salinity, temperature, and pH. Rapid fluctuations can cause severe osmotic shock, leading to stress, failed molts, or immediate death. It is highly recommended to use a slow drip acclimation method over several hours when introducing them to a new aquarium. Consistent water quality and stability are paramount for their long-term survival and health.
Calcium and minerals
High
Proper calcium levels are essential for the Alpheus acutofemoratus to successfully build and maintain its exoskeleton. Along with calcium, trace elements like iodine and magnesium must be kept at optimal marine levels to facilitate the molting process. A lack of sufficient calcium can result in soft shells, deformities, and ultimately fatal molting complications. Regular water changes with high-quality salt mix usually provide adequate amounts of these crucial minerals.
Molting
Yes
Molting is a vulnerable time for the Alpheus acutofemoratus, during which it sheds its old exoskeleton to grow a new, larger one. Following a molt, the invertebrate will hide in the rockwork for a few days until its new shell hardens completely. During this period, they are highly susceptible to predation and physical damage from tank mates. It is best to leave the discarded exoskeleton in the tank, as they often consume it to reclaim valuable minerals.
Reproduction
Oviparous
Breeding the Alpheus acutofemoratus in a home aquarium can be challenging due to the complex larval stages and dietary needs of the offspring. These invertebrates often carry their eggs under their abdomen until they hatch into planktonic larvae. Raising the delicate larvae requires specialized rearing tanks and constant supplies of specific microscopic live foods. Although spontaneous spawning is common in well-fed adults, successful rearing to maturity is rarely achieved by casual aquarists.
Compatibility & tankmates
Reef safe
The Alpheus acutofemoratus is generally peaceful and can be safely housed with a wide variety of reef-safe fish and corals. Care should be taken to avoid keeping them with large, aggressive fish such as triggerfish, puffers, or large wrasses that might view them as a meal. They are usually tolerant of other peaceful invertebrates, though some territorial squabbles may occur with closely related species. Providing ample hiding spots among live rock will help them feel secure and reduce stress.

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.

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Last updated: 06/30/2026
Sharp-femured Pistol Shrimp (Alpheus acutofemoratus) Care Guide & Tank Setup | Atlarium