What's a Mantis Shrimp?

Is having a mantis shrimp in your aquarium considered a pest or a pet?

Mantis Shrimp

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While investigating the mantis shrimp, we found mixed emotions about these marine animals. Some aquarists feel that they make an interesting, intriguing, and enjoyable pet to have in an aquarium, while others feel they are the total scourge of any aquarium. Let's take a look at their characteristics and nature to learn more about them; then you can decide for yourself if you want to keep one or not.

What Are Mantis Shrimp?

Found in tropical waters worldwide, hey fit into the Crustacea phylum in the class Malacostraca, subclass Hoplocarida (which means "armed shrimp"), and order Stomatopoda. They are most often referred to as Stomatopods and come in what seems like an endless variety of species. Because they are carnivores and will eat just about anything and everything, they are experts at catching and killing prey, being very clever, stealthy hunters. They are solitary animals, and unless you have a very large tank, they should be kept alone.

There are two hunting categories, the "spearers" and the "smashers." The "​spearers" use their spear-like claw to silently stab soft-tissued prey. The "smashers" use their forceful, club-like claw to hit, crack open or pulverize harder bodied prey. It is interesting that the power of the "smashers" appendage can produce a blow close to the power of a .22-caliber bullet and are notoriously known as "thumb splitters." It is rumored that because of the tremendous strength a mantis shrimp can have, they can crack aquarium glass!

Fun Fact

Mantis shrimp are not related to shrimp but are referred to as shrimp because of their front appendages and how they use them to capture food. They are called a "mantis" shrimp due to the fact they resemble the appearance and have the same hunting characteristics of a praying mantis insect.

These animals are burrowers and can create tubes or cavities in sand, rubble or mud. They will adapt to living in holes, cracks or crevices in rocks, and may take up residence in snail or hermit crab shells as well. A mantis shrimp could even unexpectedly show up in your tank because it hid (too successfully) on a live rock—they are masters at hiding!

The mantis shrimp is no wimp; some species can reach up to a length of about 12 inches. You can find a very large six- to eight-inch, black and white striped species while walking the mudflats in Hawaii that are not to be taken lightly.

Common Sign of a Mantis Shrimp

When fish, crustaceans, and invertebrates begin to mysteriously disappear from your aquarium without a trace, the first assumption a lot of aquarists make is that a mantis shrimp is the culprit. Even though this is a prime sign that a mantis shrimp may be present in your tank, it sometimes can be a premature conclusion as well. There are other marine animals that can contribute to this same problem. Do consider a mantis shrimp as the culprit, especially if fish are disappearing, but also investigate other possibilities thoroughly before you start driving yourself nuts looking for one.

Popping Noises: Mantis Shrimp vs. Pistol Shrimp

Some say when you hear clicking, popping or snapping noises coming from your tank, you have a mantis shrimp. Others say this is not so, that you have a pistol shrimp and not a mantis shrimp.

Obviously, if you already have a pistol shrimp, you should suspect the sound is being made by a pistol shrimp. That not withstanding, pistol shrimp are unlikely candidates for attacking or killing fish. They will, however, punch holes in hermit crab, snail, and other mollusks shells to kill and eat the animals in them.

Since these animals are natural burrowers, creating tubes or cavities in sand, rubble or mud, look for holes or tunnels in the substrate. These are usually accompanied by a mound of sand or substrate rubble piled up outside the hole. Pistol shrimp have this character trait as well, so if you find a hole like this, just dim the tank lights and sit back to see what comes out.

Mantis Shrimp: Pest vs. Pet

In the aquarium hobby, mantis shrimp are made out to be the worst, monstrous creatures that have ever inhabited oceans or aquariums. For those marine aquarists who have lost many valuable specimens to a mantis shrimp, you can see their point of view as to why they have this reputation.

However, if a mantis shrimp is accidentally introducing into your tank while adding some new live rock, what do you expect from a carnivorous creature like this? Is it the shrimp's fault it ended up in your tank and began to eat everything in it? Mantis shrimp may seem to be monsters, but they are just doing what they naturally do: hunt.

Some aquarists love mantis shrimp and enjoy their company. They are hardy and difficult to kill, aren't picky about tank water conditions or filtration, are easy to feed and cheap to maintain. This is not to say that if you have one you should neglect their tank environment, but just to make the point that they are easy to care for and are not very demanding like a lot of other marine animals can be. Whenever you decide to keep any marine animal, the responsibility to properly care for it is expected. You, as their caretaker, should respect that!

The question of whether intentionally adding a mantis shrimp to a fish-only or reef tank is bad, the answer to this is an unequivocal, yes!. If you do put one in an aquarium with other animals, don't get mad at the shrimp if things start disappearing. If you decide you want to buy a mantis shrimp or keep one, because of its territorial and aggressive nature, it is best kept it in a tank by itself, but several may be kept together if you have a very big tank with plenty of room.

How to Remove Mantis Shrimp from an Aquarium

When removing a mantis shrimp, it is not always an easy task. It takes patience and time. If one method doesn't work, try another.


Always wear a pair of heavy protective gloves when dealing with mantis shrimp.

  • Force it out with a stream of water. If you have found it has taken up residence in a piece of live rock, watch and wait patiently for it to go into its cavity (hole). Because your live rock may have other marine life on it that you do not want to lose, remove the piece of live rock and place it in a bucket or container with saltwater once the shrimp is in the rock. Pick up the rock, and using a turkey baster or syringe, squirt fresh water into the hole. The shrimp should either come flying out of the hole, or eventually coming out after many squirts, and patience.
  • Dunk the rock in fresh water. Dip or place the rock into a bucket of fresh water, but only use this method if you are not concerned about losing any other marine life that may be living on the rock.
  • Wait it out. You can remove the live rock and place it in a bucket, container, or just the sink without any water at all. With patience and baiting the mantis shrimp may crawl out on its own, but this does not always work well. The shrimp can be as patient and persistent as you, and it turns out to be a waiting game.
  • Catch it at night with a net. To do this, you should wait until the night. Mantis shrimp are nocturnal feeders, so they are best caught out in the open at night in a dark tank. Once again, sitting, waiting, watching and moving quickly can work if you can catch them out in the open away from their burrow or cavity by scooping them with a net.
  • Use natural predators like triggerfishes to combat them.
  • Buy or make a trap. There are many commercial traps on the market designed specifically for catching mantis shrimps, or you can build your own.

What to Do With a Mantis Shrimp

Once you remove the mantis shrimp from your tank, you have several options for what to do with it.

  • Keep it and provide it with a tank of its own to live in.
  • Ask a friend if they want it. There are aquarists who love and enjoy keeping mantis shrimps!
  • See if a local fish store with take it. They may even pay you for it.
  • Contact a public aquarium in your area. They may be interesting in having it.