The Pistol shrimp or Snapping shrimp is an impressive, unique, and desirable marine invertebrate. It is known for its snapping claw “the Pistol” that creates a loud sound and immense force capable of knocking out small inverts and fish.
If you are wondering whether a little critter with such enormous ability can be kept in a saltwater aquarium, the answer is yes! Most varieties of Pistol shrimp are reef-safe, compatible with corals and non-aggressive fish, and fairly easy to care for.
This article provides valuable insights into the captive care of Pistol shrimp, without further ado, let’s get into it.
Quick Notes about Pistol Shrimp
|Scientific Name||family Alpheidae|
|Tank size (minimum)||30 gallons (~120 liters)|
|Size||up 3 – 5 cm (~1 – 2 inches)|
|Optimal Temperature||24 – 28°C (~75°F – 82°F)|
|Water type||SG = 1.021 – 1.025|
|Optimal PH||8.1 – 8.4|
|Optimal KH||7 – 12|
|Nitrate||Less than 20 ppm|
|Diet||Mostly Carnivore / Omnivore|
|Temperament||Reef Safe with caution|
|Life span||up to 4 years|
|Color Form||Lots of color variations (White, green, red, brown, etc.)|
Origin of Pistol Shrimp
The Pistol shrimp belongs to Alpheidae — a family of caridean shrimp. Members of this family can be easily recognized by the presence of asymmetrical claws, with the larger claw being capable of producing a loud snapping sound.
Alpheidae comprises over 600 species grouped in about 38 genera. Notably, the largest of these genera are Alpheus and Synalpheus with over 250 and 100 species respectively.
The taxonomical hierarchy of the Pistol shrimp goes thus:
Synonyms: Snapping shrimp, Alpheid shrimp.
Habitat of Pistol Shrimp
Pistol shrimps have a cosmopolitan distribution, and they are commonly found in coral reefs, oyster reefs, submerged seagrass flats and muddy estuaries.
Majority of the genera and species of Pistol shrimp dwell in tropical, temperate coastal and marine waters, whereas Bataeus lives in cold seas and Potamalpheops inhabits freshwater caves.
Description of Pistol Shrimp
Most snapping shrimp are very small, about 3-5 cm (1-2 inches) in body length.
This shrimp has two asymmetrical claws; a normal claw and a specialized (snapping) claw. It is noted for this disproportionate large claw; which is often larger than half the length of the shrimp’s body.
The Pistol shrimp’s snapping claw can either be on the left or right arm, and it can actually reverse during its lifetime. When the shrimp loses its snapping claw, the existing (smaller) claw will molt and modify into a snapping claw, whereas the lost claw will regenerate into a smaller claw.
Also, this snapping claw does not have typical pincers, instead, it consists of two distinct parts, one of which is referred to as the “hammer”. The hammer part draws backward into a right-angled position and when released, snaps rapidly into the other part of the claw (the fixed part), hence resulting in a powerful shockwave.
It is also believed that the Pistol shrimp have poor eyesight (nearly blind), though this is not completely true.
In the aquarium, their lifespan ranges from 3 – 4 years as pets.
Behavior of Pistol Shrimp
By actively burrowing on the substrate, Pistol shrimps will create a perfect refuge for themselves where they will spend the majority of their time.
Although they are very shy animals, you should still use caution when keeping them in the same tank with smaller invertebrates and fish.
The shrimps are nocturnal and like to spend daylight hours in dimly-lit areas, they will excavate underneath rocks, and pick off leftover food from the open areas of your reef tank whenever they feel the urge to.
Cleaning is like a chore to them, they make sure to clean up the inside of their sandy burrows as well as the surroundings, being scavengers makes it a whole lot easier.
Snapping shrimps are socially monogamous and territorial. Certain situations may prompt the Pistol shrimp to display aggression towards other tank inhabitants, although disposition varies amongst species. Varieties from the Carribbean tend to be more aggressive than many other species. Moreover, they love to be left alone, otherwise, they won’t even think twice before attacking any tankmate that disturbs it or its host.
Whenever it is needed the pistol shrimp can be a superb hunter. It detects nearby preys with its antennae and immobilizes them with the aid of the snapping claw. This claw serves as a defensive mechanism; being capable of knocking out or killing small fish, shrimps, starfish, and crabs, and also warding off attacks from large predators.
Another distinct behavior observed amongst Pistol shrimps is the communication between individuals using snaps. They use the snap frequency and speed of water jets emitted by the snaps to relay information, in addition to chemical signals.
Interesting fact: A genus of Pistol shrimp, Synalpheus, forms colonies containing hundreds of individuals and live inside sponges. This is the only genus that has social behavior.
This advanced social organization amongst organisms is known as eusociality. Here, the colony formed is ruled by a large single breeding female (the queen) and a reproductive male. The majority of the castes are males, grouped into workers tasked with brood care and soldiers that defend the colony from predators.
The Snapping Technique
The Pistol shrimp is renowned for its powerful snapping ability. Basically, the shrimp utilizes its large claw as a communication tool and a weapon. It produces a loud snapping sound by a rapid closure of the claw and this snapping sound is touted as one of the loudest sounds in the ocean.
Just to give you an idea, a lion roar usually averages around 115 decibels, jet take-off – 150 decibels. The Pistol shrimp snap produces an incredible 210 decibels underwater.
Interesting fact: During the Second World War the Americans used pistol shrimp colonies sound as an acoustic screen to hide their submarines!
As the plunger slams into the socket, a high-velocity water jet is created (attaining a speed of about 100 km/h). This high-velocity water jet forms tiny bubbles that can implode within a very short time. The resulting force or shockwave is capable of stunning a prey or even killing it instantly.
Studies have revealed that the sonoluminescence (flash of light) produced from the collapse of the cavitation bubble actually reaches an extreme temperature similar to that of the sun which is estimated to be around 5,505 degrees Centigrade.
This intense flash of light created by the snap is not visible to the naked eye and lasts for about 300 picoseconds to 10 nanoseconds.
Pistol Shrimp and Relationship with Shrimpgobies
Pistol shrimps have the ability to form relationships with certain species of Goby fish— the Shrimpgobies through symbiosis. For instance, the Tiger Pistol shrimp (Alpheus bellulus) is capable of bonding with the various genus of Shrimpgobies such as Amblyeleotris, Cryptocentrus, Stonogobiops, same goes for the Randall’s Pistol shrimp (Alpheus randalli).
In this mutualistic relationship, the Pistol shrimp digs a burrow and maintains it, and both of them share the burrow. The goby’s role is to watch out for danger since it has a better vision, and the shrimp stays in sync by placing one of its antennae on top of the goby.
When a predator is sighted, the goby notifies the shrimp by flicking its tail, and both safely retreat into the burrow.
Feeding Pistol Shrimp
Pistol shrimps are scavengers and primarily detritus feeders, hence it is not unusual to spot them on the substrate feeding on detritus.
Feeding. The tiger pistol shrimp is a carnivore, preying primarily on small invertebrates. It may also eat detritus and macroalgae, and will scavenge carcasses near its burrow. If it has formed a symbiotic relationship with a goby, the goby may bring it food.
Apart from detritus, they will also accept small meaty foods such as:
- brine shrimp,
- mysis shrimp,
- as well as flake and sinking pellet foods.
Additionally, consider placing meaty foods and/or pellets near the entrance of the burrow to be sure your shrimp gets enough to consume.
Are Pistol Shrimp Coral Safe?
There is no need to worry that the Pistol shrimp can start picking on your corals or destroying colonies of zoas, etc. Pistol shrimp do not eat corals, and therefore they are safe for reef tanks in that sense.
Interesting fact: According to the study, the Pistol shrimp Synalpheus neomeris, living on corals of the genus Dendronephthya, can protect its host against two different nudibranchs feeding on soft coral polyps This protective behavior appears similar to previously known relationships between coral crabs and pistol shrimps living on stony corals.
However, there are other potential problems you should be aware of:
- Pistol shrimp like to steal frags and move them around. They also use them as materials to build their burrows. So, plucking coral frags off the rocks is the main problem you might have in your reef tank.
- Other complaints are sand storms from burrowing. They are like little bulldozers. Pistol shrimp move the gravel and sand constantly because they never stop tunneling. They can throw the excavated sand on corals, therefore, put your corals 8+ inches (20 cm) up from the sand bed.
Tank Requirements and Water Parameters
The recommended tank size for housing the Pistol shrimp is a minimum of 30 gallons (120 liters), larger tanks are even better.
This provides enough room for the shrimp to roam and helps it avoid close contact with other critters in the reef tank. Do not underestimate how important that is! Small tanks will increase aggression in Pistol shrimp.
Temperature: The ideal temperature range for keeping Pistol shrimp is 75 – 82 °F (24 – 28 °C).
pH: Keep the pH between the values 6.5 – 7.5.
Hardness: Optimal water hardness values is between 8 – 12 dKH.
Salinity: 1.024 – 1.026, 1.025 is ideal.
Calcium: 400 – 450 ppm
Magnesium: 1250 – 1350 ppm
Nitrates: < 10 ppm
Phosphates: < 0.1 ppm
Light is not that important for the Pistol shrimp. In most cases, it will avoid it for most of the time.
Therefore, basically, Lighting should be adapted to the needs of the reef tank.
Substrate and Decorations:
The Pistol shrimp prefers sandy bottoms which it can burrow deeply into and create a fortress for itself and a host gobyfish. Therefore, 2+ inches (5 cm and more) of depth will be much appreciated.
Note: Keep in mind that fine sand can get carried around the tank by the water flow once tossed. Corals sitting on the sand may be buried.
They also need small rubble pieces to build up tunnel walls. Be sure to provide plenty of rockwork, this will make the shrimp more comfortable.
Tip: Because of the endless burrowing and remodeling the shrimp usually do, you will have to ensure that your rocks are is secure. Otherwise, the shrimp can undermine the sand it is resting on and you will have an avalanche of rock work and corals.
Caring and Keeping Pistol Shrimp
Taking care of the Pistol shrimp is relatively easy, start by making sure that the invert has plenty of room to explore.
Although the shrimp spends so much time in its lair— the burrow, it will occasionally venture from its home to the open in order to feed on food items and detritus.
At this point, it would be dicey for the shrimp to encounter other shrimps, crabs, and small fish, especially if they charge at it. Meanwhile, keeping this shrimp in a very large tank is the best way to minimize this issue.
Furthermore, ensure that all rockworks are secure because the shrimp may form deep burrows around the base, causing them to collapse.
Be sure to feed your shrimp regularly. In the same vein, provide mineral & iodine supplements to keep it healthy and aid with the strenuous molting process. In addition, it is important to carry out regular water changes to keep the water clean and replenish the needed minerals.
It is important to drip-acclimate the shrimp before adding it to the reef tank, that way, it will adjust to the new water conditions thereby eliminating shock. Keep the tank conditions stable as inconsistency in water parameters can affect the health of your shrimp.
Do it very slowly and remember to check the temperature is correct before adding the Pistol shrimp to the tank. Also, be careful as shrimp can jump fast and high when you try and net them.
Breeding Pistol Shrimp
The reproductive cycle of this species is linked to the molt cycle of the female shrimp. They engage in a monogamous mating system which allows them to retain the same mate after initial copulation.
The females are usually sexually receptive after molting. Unpaired individuals signify readiness to mate using chemical signals and by producing snaps with their specially adapted claws.
Both shrimps (male and female) will form a mating pair and mate at the right time during the female’s molt cycle. Throughout this period, the male will provide protection for the female while she molts (sheds her exoskeleton).
This pairing system provides mutual benefits to both parties, the male gains access to several mating opportunities whereas the female is relieved from having to search for a mate while in her vulnerable molting state.
Depending on the species, the number of eggs per brood can range from a few hundred to several thousand in females.
After fertilization, the eggs will spend an estimated duration of 4 weeks (28 days) before hatching.
Additionally, larval development usually occurs in three stages separated by a series of molts.
- The first stage lasts 1-2 hrs during which enlargement of the organism occurs. Interestingly, some shrimps are hatched at a body size enough to commence the second larval stage, thus skipping the first larval stage.
- The second larval stage lasts 28 hours and the eyes and appendages formed to develop further. In this stage, the larva will survive on nutrients present in the egg yolk until it forms functional mouthparts for feeding.
- The third stage lasts for 2-3 days, after which the shrimp enters the post-larval stage and assumes the form of an adult shrimp.
Pistol Shrimp and Compatible Tankmates
Keep in mind that compatible tankmates for the Pistol shrimp vary amongst species, for instance, the Randall’s and Tiger Pistol shrimp can easily pair with many varieties of shrimpgoby without problems.
Interesting Facts: According to the study, more than 30 species of this shrimp genus live in such an alliance. However, biologists reported that a porcellanid crab (Pachycheles rudis) can be a third partner in shrimp (Betaeus setosus)–goby associations.
They often use a signal system, consisted of antennal contact of the shrimp with the fish and tail undulations by the fish (Watchman gobies). If the fish indicates danger by fluttering the caudal fin or even by fleeing into the tunnel the shrimp rapidly retreats.
On the contrary, species like the Red Carribbean Pistol doesn’t fancy pairing with gobies, instead, it prefers to live with the Curlycue Anemone (a Carribbean anemone that possess long spiralling tentacles).
The rare Pocillopora Pistol shrimp is known to dwell within colonies of Pocillopora corals. Hence, for any Pistol shrimp species you go for, endeavor to make the preferred host animal available in your reef tank.
|Pistol shrimp species||Compatible Associations|
|Tiger Pistol Shrimp (Alpheus bellulus)||Cryptocentrus cinctus, Amblyeleotris guttata, Amblyeleotris randalli or Stonogobiops yasha.|
|Randall’s Pistol Shrimp (Alpheus randalli)||Stonogobiops, Cryptocentrus, and Amblyeleotris species.|
|Fine-striped shrimp (Alpheus ochrostriatus)||C. tangaroai, A. guttata, A. randalli and A. wheeleri|
|Red Caribbean Pistol Shrimp (Alpheus sp.)||Do not usually pair with shrimpgobies. Instead, they form a relationship with the Curlycue Anemone (Bartholomea annulata).|
|Bullseye Pistol Shrimp (Alpheus soror)||Does not usually form a bond with shrimpgobies. Some individuals may share a cave with some gobies, but it is not safe for the last.|
You should lean towards the introduction of tankmates that wouldn’t harm the shrimps e.g. small non-aggressive fish, corals, and sponges, whereas predatory fish species like triggers, puffers, groupers, lionfish, and hawkfish should not be considered as ideal tankmates.
Do not keep the Pistol shrimp and the Mantis shrimp together. The Mantis shrimp is a large predator. Depending on the species, their size can reach up to 15 inches (35 cm).
In addition, besides the shockwave, they can also deal a lot of physical damage. Therefore, in most cases, the mantis shrimp will be a winner in this confrontation with the Pistol shrimp, as it has a sturdier build.
Other Shrimp, Snail, Crab Species
Even though many reef enthusiasts reported that they managed to keep Pistol shrimp with a variety of snails, shrimp, etc.; that they had never shown any interest in attacking them – it is still not recommended.
Unfortunately, there are also reports of them being on a killing spree, wiping out entire livestock in the tank.
Keep in mind that there is always a chance that these shrimp can react defensively even when there is no real threat. Therefore, generally, the Pistol shrimp is not compatible with snails, shrimps (Peppermint shrimp, Red Fire shrimp, Skunk Cleaner Shrimp, Camel shrimp, Saron Shrimp, Red-white Cleaner Shrimp, etc.), and small or young crabs (like Boxer crab, porcellanid crab, etc. ).
In addition, these shrimp need small stones and shell frags to shore up their walls. So, place a bunch near the opening of the cave. They will definitely use them. If you do not give them any, they may kill hermit crabs and snails to get their building materials.
Nonetheless, what are the most peaceful Pistol shrimp species out of all?
The best chances you will get with Randall’s Pistol/Candy cane varieties. They are considered the most peaceful species amongst aquarists. However, they won’t hesitate to charge back at any critter that threatens them. In addition, they have their own personalities and can also vary from region-of-origin to region-of-origin.
Tip: Ideally, there should not be any bottom-dwelling fish. They can stun and kill fish that accidentally came too close to their cave.
Tip #2: In addition, do not forget to feed them. Do not make them hungry or they will find food on their own and you may not like it.
Buying Pistol Shrimp
This shrimp species is available in both offline and online stores costing about $20 – $40 for a single specimen, variables like size and species can influence the price. Some stores offer shrimp/goby pairs for sale— at a higher price of course but it’s totally worth it.
While shopping, look out for specimens in good condition — having complete body parts: antennae, legs, tail, and claws. In addition, make sure to avoid specimens showing noticeable signs of lethargy.
For starters, you may want to try out the Randall’s or Candy cane Pistol shrimp, Alpheus randalli, and pair it with a white ray shrimpgoby (Yasha goby). Tiger Pistol shrimp is another good beginner species and reef-safe too, it can be easily identified with the brown, tan, and cream stripes on its body.
The Green Pistol shrimp and Bullseye Pistol shrimp are equally good species but they are less likely to pair with Shrimpgobies. Also, you should avoid the Red Carribbean Pistol shrimp because they are more hostile to tankmates than other Pistols.
What happens if a pistol shrimp hits you?
Of course, it depends on the size of the Pistol shrimp in the first place.
Large species can sting you pretty well (something like a strong rubber band hit) though it is not going to break open your skin or break bones. Nonetheless, we usually do not keep large species like that in our tanks.
Also, do not worry, even large Pistol shrimp will not break your tank. Although their snap is extremely powerful for their size, it is not strong enough to break the glass of the tank.
The small ones (like Randall’s pistols) often do not hurt at all. However, if you decide to keep Pistol shrimp in your reef tank as a pet, it is still NOT recommended to touch it with your bare hands!
Can Pistol shrimp break the glass of the tank?
Do not worry, even large Pistol shrimp will not break your tank. Although their snap is extremely powerful for their size, it is not strong enough to break the glass of the tank.
This is one of the most interesting shrimps you can possibly have in your reef tank. The Pistol shrimp is very attractive and packs a lot of personalities. Anyway, be sure to obtain reef-safe varieties like the Tiger and Randall’s Pistols and pair it with a compatible gobyfish.
The Pistol shrimp can live for 3 – 4 years in captivity, and it would only be able to attain this feat if appropriate and stable water conditions are maintained in the reef tank.
Lastly, ensure the shrimp gets enough meaty foods to eat, then keep it away from large predators and copper medications as these things can cause its demise.