# Pistol Shrimp (*Alpheus digitalis*)

> The pistol shrimp (Alpheus digitalis) snaps its claw to create a cavitation bubble that stuns prey and communicates with mates. Adults reach 5 cm and are Least Concern.

- **Category:** Invertebrate
- **Conservation status (IUCN):** Least Concern
- **Range:** Indo-Pacific reefs and burrows.
- **Canonical page:** https://globalanimalguide.org/animals/pistol-shrimp/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Arthropoda
- **Class:** Malacostraca
- **Order:** Decapoda
- **Family:** Alpheidae
- **Genus:** Alpheus

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Alpheus digitalis |
| Diet | Carnivore |
| Habitat | Reef burrows and sand flats |
| Lifespan | 2–3 years |
| Weight | 0.003–0.01 kg |
| Top speed | up to 2 km/h |
| Conservation status | Least Concern (IUCN) |

## Cavitation snap

The enlarged claw closes so fast it vaporises water, producing a bubble that collapses with a snap up to 210 decibels — stunning prey and generating a flash of heat and light.

## Worms, fish, and goby partners

Small fish and invertebrates are stunned then eaten. Many species share burrows with gobies that watch for danger while shrimp maintain the tunnel.

## Indo-Pacific reef sand

Alpheus digitalis inhabits burrows in tropical reef flats and rubble. Snapping choruses audible on quiet reefs come from colonies.

## Noisy but secure

Least Concern across extensive reef habitat. Symbiosis with gobies and cryptic burrows protect them from many predators.

## Frequently asked questions

### How loud is a pistol shrimp snap?

The cavitation pop can exceed 200 decibels — louder than a gunshot at close range.

### Why do pistol shrimp have one big claw?

The major claw is specialised for the high-speed snap that stuns prey.

### Do pistol shrimp partner with gobies?

Yes — gobies stand guard while shrimp dig; both retreat into the shared burrow when threatened.

### Can pistol shrimp break glass?

Colonies in aquariums can crack thin glass with repeated snaps — a known hobby hazard.

### What do pistol shrimp eat?

Small fish, worms, and crustaceans stunned by the cavitation snap.

---
Source: Global Animal Guide (https://globalanimalguide.org/animals/pistol-shrimp/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.