Mantis Shrimp - Interesting Creatures that are Worth Being Kept in an Aquarium
Whist often refered to as shrimp, Mantis Shrimp (aka Stromatopods) are only distantly related to the more familiar decapod crustaciens such as prawns, crabs and shrimp.
Stromatapods come in two main forms, the smashers, which have club-shaped raptiorial appendages, and the spearers, that have spear-like raptiorial appendages. However, dispide their various forms, all Stromatopods are CARNIVOROUS. The specifics of diet will be covered later in this article.
A common misconception is that if you have a Stromatopod in your tank, you are likelty to have all of your fish and other tank inhabitants decimated in the course of a few days. Although it is true that certian species do specilise in capturing and feeding upon fish (ie. spearer species such as those found within the genus Lysiosquillina), many species (ie. those found within the genus Chorisquilla, Gonodactylus and Odontodactylus) are much more specific in their dietry requirments and are likely to ignore fish and target your clean-up crew, prefering to feed upon gastropods, crabs and shrimp. However, Stromatopods are not mindless killers that will not stop until all potential prey is killed. My experience is that they will only kill and eat when hungry. A video of one of my Stromatopods hesitating to "kill" an animal that is could easily overpower is shown below.
To obtain their prey, the "spearing" species will use their raptiorial forelimbs to spear passing prey (usually fast moving animals), in a similar fashion to a preying mantis (thus the name mantis shrimp). However, "smasher" species locate their prey (generally slow moving animals), and then begin to hammer away at it with their club-shaped raptiorial forelimbs. The complexity of the hunting method of the latter type has only just been fully appreciated. Smasher Mantis shrimp have the FASTEST hunting strike known to occur in nature. Their strike is so fast that CAVITATION (ie. the formation and their the immediate implosion of cavities in a liquid) occurs. This destrictive force amplifies the innitial strike to the prey.
Despite their carnivorous nature, Stromatopods will not feed upon corals, however some of the smasher types (eg. Gonodactylus smithii) will smash into living coral skeletons to form a hole within which they will reside.
Structurally, Stromatopods are one of the most complex crustaceans in the ocean. In all of nature, they have the most complex eye structure. Although Stomatopods have compound eyes, like all other crusteaceans, their eyes contain more photoreceptor types than any other animal described. Morphologically, their eyes have been divided into a mid-band and two laterally placed hemisphere regions. Each of these regions is designed for a descrete purpose (ie. 2 - channel polarising filter system, 12 channel colour vision system, and a lins scan sampling arrangement). Although scientists have understand the structure of stromatopod eyes, their biological significance is not fully understood.
Given that relatively little is known regarding the biology of Stromatopods, hobbiest have the oppertunity of observe these creatures and positivitly contribute to the scientific understanding of these remarkable creatures.
In relation ot captive husbandary, different Stromatapod species vary in their ease of keeping. Generally those species from intertidal areas (and the species most likely to be found as hitch-hikers in live-rock) such as those within the genus Gonodactylus are the hardiest of all species. When you consider that these species are often out of water at low tide, flooded by fresh water during heavy rainfall events and flooded by marine water at high tide, it is not surprising that they are so tough! Those species that come from reef areas such as the Peacock Mantis Shrimp (Odontodactylus scyllarus) are a little less hardy as conditions of the reef are generally much more stable when compared to intertidal areas. Also included in this group in terms of sensitivity to changes in water chemistry would be the burrowing species that inhabit areas of sand/rubble (ie. those within the genus Lysiosquillina).
With mantis shrimp, if you keep them under "reef quality" water conditions, all species will generally thrive. However, as these animals are invertebrates, you will have to ensure that iodine levels are maintained at "reef" levels to ensure that health issues do not arrise.
As mentioned previously, mantis shrimp vary in their dietry requirments. Generally, the spearer types target small fish, shrimp and prawns, while the smasher types target gastropod mollusks, crabs and shrimp. With time in the aquarium, all Stromatopods will learn to accept pre-killed prey and will learn that their keeper is a source of food. At this stage the stomatopods will become very interactive and will not hesitate to display "natural" behaviour in the presence of their keeper. They may even "beg for food" upon seeing their keeper.
Many of the behaivours of mantis shrimp are not fully understood. It has been stated in literature that many species of mantis shrimp are SOLITARY and should be kept by themselves. While this is true for keeping males of the same species together, I have kept pairs (ie male and female) together without issue. When housed together, reproductive behaviour may be observed. In the smasher species, this is usually initiated by the female (females lack a tube-like structure on the base of the last pair of walking legs).
After mating, the female will produce a clutch of eggs, which she will incubate alone. Upon hatching the larvae are released from the burrow for dispersal. This proces is shown in the video below.
Within Australia, the most common species of Stomatopods to be found within the aquarium trade are the smasher types within the genus Gonodactylus. These species often are trasported within liverock.
Many resources are availible on the internet related to types of Stromatopods that are commonly found within the aquarium trade. Of particular use is "Roy's List of Stromatopods for the Aquarium". This site provides a list of species commonly kept, together with information related to keeping these fantastic animals in the aquarium. The link for this site is provided below:
http://www.ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/
Stromatapods come in two main forms, the smashers, which have club-shaped raptiorial appendages, and the spearers, that have spear-like raptiorial appendages. However, dispide their various forms, all Stromatopods are CARNIVOROUS. The specifics of diet will be covered later in this article.
A common misconception is that if you have a Stromatopod in your tank, you are likelty to have all of your fish and other tank inhabitants decimated in the course of a few days. Although it is true that certian species do specilise in capturing and feeding upon fish (ie. spearer species such as those found within the genus Lysiosquillina), many species (ie. those found within the genus Chorisquilla, Gonodactylus and Odontodactylus) are much more specific in their dietry requirments and are likely to ignore fish and target your clean-up crew, prefering to feed upon gastropods, crabs and shrimp. However, Stromatopods are not mindless killers that will not stop until all potential prey is killed. My experience is that they will only kill and eat when hungry. A video of one of my Stromatopods hesitating to "kill" an animal that is could easily overpower is shown below.
To obtain their prey, the "spearing" species will use their raptiorial forelimbs to spear passing prey (usually fast moving animals), in a similar fashion to a preying mantis (thus the name mantis shrimp). However, "smasher" species locate their prey (generally slow moving animals), and then begin to hammer away at it with their club-shaped raptiorial forelimbs. The complexity of the hunting method of the latter type has only just been fully appreciated. Smasher Mantis shrimp have the FASTEST hunting strike known to occur in nature. Their strike is so fast that CAVITATION (ie. the formation and their the immediate implosion of cavities in a liquid) occurs. This destrictive force amplifies the innitial strike to the prey.
Despite their carnivorous nature, Stromatopods will not feed upon corals, however some of the smasher types (eg. Gonodactylus smithii) will smash into living coral skeletons to form a hole within which they will reside.
Structurally, Stromatopods are one of the most complex crustaceans in the ocean. In all of nature, they have the most complex eye structure. Although Stomatopods have compound eyes, like all other crusteaceans, their eyes contain more photoreceptor types than any other animal described. Morphologically, their eyes have been divided into a mid-band and two laterally placed hemisphere regions. Each of these regions is designed for a descrete purpose (ie. 2 - channel polarising filter system, 12 channel colour vision system, and a lins scan sampling arrangement). Although scientists have understand the structure of stromatopod eyes, their biological significance is not fully understood.
Given that relatively little is known regarding the biology of Stromatopods, hobbiest have the oppertunity of observe these creatures and positivitly contribute to the scientific understanding of these remarkable creatures.
In relation ot captive husbandary, different Stromatapod species vary in their ease of keeping. Generally those species from intertidal areas (and the species most likely to be found as hitch-hikers in live-rock) such as those within the genus Gonodactylus are the hardiest of all species. When you consider that these species are often out of water at low tide, flooded by fresh water during heavy rainfall events and flooded by marine water at high tide, it is not surprising that they are so tough! Those species that come from reef areas such as the Peacock Mantis Shrimp (Odontodactylus scyllarus) are a little less hardy as conditions of the reef are generally much more stable when compared to intertidal areas. Also included in this group in terms of sensitivity to changes in water chemistry would be the burrowing species that inhabit areas of sand/rubble (ie. those within the genus Lysiosquillina).
With mantis shrimp, if you keep them under "reef quality" water conditions, all species will generally thrive. However, as these animals are invertebrates, you will have to ensure that iodine levels are maintained at "reef" levels to ensure that health issues do not arrise.
As mentioned previously, mantis shrimp vary in their dietry requirments. Generally, the spearer types target small fish, shrimp and prawns, while the smasher types target gastropod mollusks, crabs and shrimp. With time in the aquarium, all Stromatopods will learn to accept pre-killed prey and will learn that their keeper is a source of food. At this stage the stomatopods will become very interactive and will not hesitate to display "natural" behaviour in the presence of their keeper. They may even "beg for food" upon seeing their keeper.
Many of the behaivours of mantis shrimp are not fully understood. It has been stated in literature that many species of mantis shrimp are SOLITARY and should be kept by themselves. While this is true for keeping males of the same species together, I have kept pairs (ie male and female) together without issue. When housed together, reproductive behaviour may be observed. In the smasher species, this is usually initiated by the female (females lack a tube-like structure on the base of the last pair of walking legs).
After mating, the female will produce a clutch of eggs, which she will incubate alone. Upon hatching the larvae are released from the burrow for dispersal. This proces is shown in the video below.
Within Australia, the most common species of Stomatopods to be found within the aquarium trade are the smasher types within the genus Gonodactylus. These species often are trasported within liverock.
Many resources are availible on the internet related to types of Stromatopods that are commonly found within the aquarium trade. Of particular use is "Roy's List of Stromatopods for the Aquarium". This site provides a list of species commonly kept, together with information related to keeping these fantastic animals in the aquarium. The link for this site is provided below:
http://www.ucmp.berkeley.edu/arthropoda/crustacea/malacostraca/eumalacostraca/royslist/
