By Bob Goemans
Site Supported in Part by:
Champion Lighting and Supply 


Alpheus armatus

Rathbun, 1901

Pistol Shrimp

Likely Reef Tank Suitable

Likely Fish-Only Tank Suitable

Range: Western Atlantic Ocean: West Indies, the Bahamas, southern Florida and Puerto Rico.

Size: 1.5 inches (4 cm)

Natural Environment: Shallow coral reef environments and usually associated with the anemone Bartholomea annulata.

General Husbandry: Rarely available in the home aquarium trade.

Once in the aquarium, rarely seen, yet usually heard at night by snapping the fingers of its single, yet exceptionally large claw. Loud enough to awake light sleeping aquarists.

Best maintained in reef aquariums with hiding places or fish-only aquariums with lots of live rock for protection and possibly a host goby.

As to diet, late evening snacks of meaty foods, e.g., small strips of fresh fish/shrimp flesh, sinking shrimp pellets or meaty freeze-dried foods placed near the area where it hides during the daytime will help reduce the nose it makes at night while hunting and/or provide some of its nutritional needs.

Has red-brown and white antennae and in the wild, usually digs a cave next to an anemone.


    Kingdom: Animalia

    Phylum: Arthropoda

    Class: Malacostraca

    Order: Decapoda

    Family: Alpheidae

    Genus: Alpheus

FYI: Nocturnal.

May eat small shrimp, snails and tubeworms.

Experience Level: Intermediate

Diet: Carnivore

Temperament: Peaceful

Aquarium Environment: Reef or fish-only aquarium

Coral Safe: Yes

Fish Safe: Yes

Invertebrate Safe: With caution

Acclimation Time: Shrimp are 'very' sensitive to specific gravity/salinity changes. Therefore, be sure to adjust the bag's water to that of the aquarium in which it will be placed by slowly adding small amounts of aquarium water to the bag every few minutes. In most cases, this process should take at least 15 minutes.

Aquarium Hardiness: Moderately hardy

Calcium (Ca): 380 - 430 mg/l

Alkalinity: 2.5 - 3.0 meq/l

Phosphate (PO4): <0.05 mg/l

Magnesium (Mg): approx. 1350 mg/l (relate to specific gravity) Extremely important for molting!

Strontium (Sr) 8 - 10 mg/l

Iodine (I) Trace element additives containing iodine should be used as recommended by their makers, as iodine is also vital for the molting process.

Temperature Range: 74 - 79°F (23 - 26°C)

Minimum Tank Size: 30 gallons

Lighting: PAR ratings N/A

Water Movement: WM 1 - 2

Specific Gravity: 1.023 - 1.025

pH: 8.0 - 8.4

 Alpheus armatus (Pistol Shrimp)
Photo ©
Site Supported in Part by: