Marine Shrimps - An Introduction

By Scott W. Michael

The Crustaceans are one of the most popular invertebrate groups with scuba divers, underwater photographers and chefs. Many are odd in form, display beautiful color patterns, exhibit interesting life history modes and some are good to eat! Of all the crustaceans, the shrimps are probably the most popular with aquarists, and for good reason. Most of the shrimps tend to be less destructive than their crustacean cousins. There are also a number of shrimp species that are brightly colored, interesting to watch and they tend to be less secretive than certain crabs and lobsters. Some shrimps are also sought after because of the valuable services that they provide for the aquarium or their tankmates.

In this article series, we will examine the biology and captive care of the decapod shrimps that are available to aquarists. Hopefully, this article will facilitate your efforts to select a shrimp that is right for your aquarium and aid you in keeping them healthy.

Decapod Shrimps - An Introduction

The crustacean order Decapoda is comprised of the crabs, shrimps and lobsters. There are about 8,500 species in the order, most of which live in marine environments. The general crustacean anatomy consists of a head, thorax, abdomen and tail. The head has five pairs of appendages. The pair nearest the end of the head are called the antennules. The next pair are known as the antennae. The next pair of head appendages are known as mandibles. These are shorter and well-suited for holding, grinding, biting and pushing food into the mouth. There are also two pairs of accessory feeding appendages, which vary in structure depending on the food habits of the species in question.

The trunk (which can be further divided into the thorax and the abdomen) is usually covered with a carapace, which encloses the entire body. The carapace serves as protection from at least some predators. The trunk has numerous pairs of legs, which are important in food gathering, swimming, crawling, sperm transmission and egg brooding. There are also appendages under the abdomen called pleopods or swimmerets. These are used for swimming, for brooding eggs and during copulation. The tail of the shrimp is comprised of a telson and flattened appendages known as uropods, and is used when they swim backwards.

The decapods have maxillipeds (these are the first three thoracic appendages), and five pairs of legs. In the shrimps, there are pincers on the first two or three pair of legs. The gills of the decapods are located within branchial chambers under the fused head and thoracic carapace. The shrimps and lobsters have long abdomens, while crabs have a small abdomen that is folded under the rest of the body. The decapod shrimps should not be confused with other crustaceans that are called shrimp (e.g., mantis shrimps, mysid shrimps).

The shrimps that are most often encountered by aquarium keepers belong to the families Alpheidae (snapping shrimps), Gnathophyllidae (bumblebee shrimps), Hippolytidae (cleaner shrimps), Hymenoceridae (harlequin shrimps), Palaemonidae (commensal shrimps), Rhynchocinetidae (hingebeak shrimp) and Stenopodidae (boxer shrimps). Let's take a brief look at each of these families.

Alpheidae (Snapping Shrimps)

The snapping or pistol shrimps have eyes on short stalks. In some species, the eye stalks are so short that their vision may be obscured by the surrounding carapace. These shrimp also have one enlarged chelae (i.e., pincer, claw) which can be rapidly snapped shut. This results in an audible popping sound. While the snapping shrimps have been reported to use their claws to stun their prey and to ward off predators, its primary function is to warn potential rivals of their territory boundaries. Most of the snapping shrimps are found in both reef habitats (where they are very cryptic and rarely seen) and on adjacent sand substrates. The reef-dwelling species lurk within stony coral colonies, within reef crevices, in sponges, tunicates, or between sea urchin spines. The Red Snapping Shrimp (Alpheus armatus), a species from the Atlantic Ocean, associates with the Curleycue Sea Anemone (Bartholomea annulata), while some members of the genus Synalpheus live among the feather-like appendages of the crinoids or share a burrow with burrowing mantis shrimps.

The sand-dwelling snapping shrimps create their own burrows. Some of these form unique partnerships with certain gobies. These shrimps are vulnerable to being attacked by predators as they push sand and debris out of the entrance of their burrows. Their goby partners act as sentinels, warning the crustaceans of impending danger. The shrimp will typically place an antennae on the tail section of the fish. When the goby detects a potential threat, it will wag its tail to warn its crustacean burrow mate. These snapping shrimp-goby pairs make for a unique and interesting display in the home aquarium. If you want to keep a snapping shrimp-goby pair, you should purchase the animals together to ensure you obtain animals that will form a mutual bond. Fortunately, LiveAquaria.com often sells a goby or pair of gobies with the appropriate shrimp partner.

Some snapping shrimps that end-up in the home aquarium are introduced inadvertently. These individuals are added along with live rock or stony coral colonies and are often heard (snapping) but never seen. The snapping shrimps, especially the burrowing forms, can provide an important function in the reef aquarium by turning and stirring the substrate. But this can also be problematic - if rock work is not suitably placed on the aquarium bottom their digging activity may cause cave-ins. This can be prevented by putting rock directly on the glass bottom and adding the sand around the rocks. Some burrowing snapping shrimp will battle each other for territory, unless they are of the same sex, then they will often share a burrow. The larger alpheids may prey on smaller shrimps or more diminutive, bottom-dwelling fishes. There are reports of snapping shrimps killing and eating their goby associate, when the latter were emaciated or ailing, but this rarely occurs.

Gnathophyllidae (Bumblebee Shrimps)

These are stubby little shrimp with a short rostrum that often exhibit interesting color patterns (usually either contrasting stripes or bright spots). They have pincers on the first and second pair of legs. Most live under rubble, or in reef interstices and sponges. There are a few species that live among sea urchin spines or on sea cucumbers. Some of the gnathophyllids actually feed on echinoderm tube feet, while others eat detritus. At least one species is known to be a cleaner that services cryptic fishes. The bumblebee shrimps tend to be quite small (a maximum length of around one inch) and live secretive lives.

Because they tend to spend most of their time hiding, the bumblebee shrimps do not make very good display animals. You may be able to observe them at night if you use a red incandescent or fluorescent bulbs over the aquarium. The bumblebee shrimps are also best kept in small aquariums (e.g., nano-reef), which will enable you to better relocate and observe them.

Hippolytidae (Cleaner Shrimps)

While the common name "cleaner shrimps" is somewhat misleading, because many of the members in this family do not clean, the best known members of the family regularly remove parasites and necrotic tissue from receptive fishes. The client fish will approach the cleaning station and maintain its position near the shrimp. The cleaner will "dance" as the potential host approaches, which serves as an invitation to be groomed. When the host poses (i.e., remains stationary and erects the fins or flares the gill cover nearest to the shrimp), the shrimp will climb aboard and begin inspecting and picking at the body surface with its pincers. Those shrimps that clean tend to exhibit bold color patterns and long white antennae. They usually maintain specific cleaning stations (either a cave or a crevice) that are visited by their clients.

The most popular members of the cleaning guild, and possibly of all the shrimps, are the members of the genus Lysmata. The Scarlet Cleaner Shrimp (Lysmata amboinensis) is ubiquitous in the trade and makes a wonderful aquarium resident, while the fire or Blood Red Shrimp (Lysmata debelius) is one of the most beautiful of all the aquarium shrimps. The Lysmata spp. tend to be quite hardy and sometime even reproduce in home aquariums. While the cleaning activities of these shrimps may provide some benefit to captive fishes, they will not eliminate parasite infections from their home aquarium. That said, they may reduce the number of trophonts (the ich "spots") on an infected fish.

The Lysmata spp. vary in their levels of secretiveness. Some species spend most of their time in cracks and crevices, sometimes with only the long antennae protruding. Others are bold aquarium inhabitants that parade around the tank. They make great reef aquarium inhabitants and most rarely if ever bother their invert neighbors. Keeping the Peppermint Shrimp (Lysmata wurdemanni) has another benefit. This species can be employed to control populations of the pestilent sea anemones of the genus Aiptasia. Be aware that these shrimp might also feed on the ornamental cnidarians called yellow colonial polyps. The scavenging activities of all species of Lysmata also benefit general reef tank health.

Members of the genus Saron, which are sometimes referred to as marble shrimp, are not cleaners. They are reclusive during the day, hiding in reef nooks and crannies. At night, they move onto adjacent reef areas to graze on sessile invertebrates and detritus. There are a number of Saron spp. that are still undescribed. The two most common species in the aquarium trade are the Pinecone Marble Shrimp (Saron inermis) and the Common Marbled Shrimp (S. marmoratus). There are some hyppolytid shrimps that live in sea anemones (Sexy Shrimp, Thor amboinensis), soft corals (Soft Coral Shrimp, Hippolyte commensalis) or black corals (Saw Blade Shrimp, Tozeuma armatum). Some are also found in sea grass meadows or among macroalgae.

These are some of the most highly desirable and durable of the aquarium shrimps. Most can be kept with members of their own species, or with other shrimps. In fact, they often do best when housed in pairs or groups. The fact that these crustaceans will clean makes them interesting to watch as well as beneficial to fish residents. The hyppolytid shrimps can live for up to three years in captivity.

Hymenoceridae (Harlequin Shrimps)

The family Hymenoceridae includes the most magnificent of all the crustaceans, the harlequin shrimps (Hymenocera spp.). Some crustacean experts think there is only one species in this genus, while others split the Indo-west Pacific and Central-eastern Pacific forms (the former is recognized as Hymenocera elegans while the latter would be H. picta). Both "species" of harlequin shrimp are white to cream overall with large purplish blotches with blue margins (H. elegans) or maroon with yellow margins (H. picta). The latter is most often collected in Hawaii and commands a higher price than its "western" kin. Not only are their colors spectacular, the appendages on the thorax are very ornate. There are several pair of anterior appendages that have flattened expansions. For example, the chelipeds are large and shield-like.

What is particularly interesting about the Hymenocera spp. is that they feed on sea stars. A pair of these beautiful beasties (the adults are almost always found in pairs) will drag sea stars to their lair or incapacitate them where they find them. An observant friend of mine, Ray Izumi, has observed that these shrimps will vigorously stab their sea star prey with the spike-like end of one pair of legs. It may be that the shrimp are puncturing the water vascular system of the sea star so that it cannot move off. In this way, they would be able to control some of the large asteroids that they typically feed on.

Their feeding behavior is somewhat Hannibal Lector-like. When they consume sea stars, they usually flip them over and begin feeding at the end of the arms, working their way toward the central disc. In this way, they can keep their "living buffet" fresh longer. In some cases, the shrimp will amputate an arm and let the rest of the sea star escape. Although it depends on the size of their echinoderm prey, the harlequin shrimp will take several days to several weeks to consume an entire sea star. They prefer sea stars in the genera Fromia, Linckia, and Nardoa, but will eat other species as well (including the crown-of-thorns sea star, Acanthaster planci). In the aquarium, they will also feed on sea urchins and brittle sea stars. Reef aquarists have been known to add one or a pair of these shrimps to a reef tank to deal with populations of Asterina sea stars. If you do this, make sure you are ready to provide larger sea stars once the Asterina run out. If you are willing to supply these shrimp with sea stars, they will thrive in the home aquarium. Harlequin Shrimp will even spawn in captivity.

Palaemonidae (Commensal Shrimps)

This is a large family of shrimps that are common in both temperate and tropical seas. They have enlarged pincers on the second pair of legs. The commensal shrimps are often found living in association with other invertebrates. For example, many species in the genus Periclimenes live among the tentacles of sea anemones or large-polyped stony corals. At least some members of this family actually feed on their anemone host, although they apparently do not ingest enough tissue to kill the cnidarian. There are other Periclimenes spp. that spend their lives within the spines of sea urchins or among the arms of crinoids. The Sea Star Shrimp (Periclimenes soror) most often associates with sea stars while members of the genus Dasycaris are often found on black corals.

There are members of this family, like some of the anemone shrimps, that engage in cleaning behavior. Potential fish clients will "park" or hover near an anemone occupied by displaying shrimps (they whip their antennae and chelae to-and-fro), at which time one or more of these crustaceans will leap onto the fish and pick at its skin, gills and even within the mouth.

This family includes some species that are commonly encountered in the aquarium trade. They tend to be smaller and delicate shrimps that are preyed on by a large number of different reef fishes. Those that clean, may derive some degree of immunity from predators (at least those piscine hosts that utilize their cleaning services). At least some of the smaller anemone-dwelling forms (e.g., Periclimenes holthuisi) tend to occur in groups. These species will do best if kept in pairs or in small aggregations with a suitable host sea anemone.

Rhynchocinetidae (Hingebeak Shrimp)

The hinge-beak shrimps are nocturnal shrimps that form groups under overhangs and in reef crevices. They are named for the long, serrated rostrum that is hinged at its base that enables it to be moved up and down. Male hingebeak shrimps differ from the females in the size of the chelipeds. In males, they are more elongate. Most of the Rhynchocinetids are red in color, which is a hue indicative of a nocturnal lifestyle. While they spend their days tucked away in reef interstices, they come out at night to feed. Their diets include detritus and sessile invertebrates. Some of the hingebeak shrimps, including the Ubiquitous Dancing or Camel Shrimp (Rhyncocinetes durbanensis), are found in large aggregations that can be comprised of hundreds of individuals.

There are several species in this genus that regularly make it into the aquarium trade. The most common being the camel shrimp. It is an inexpensive species that makes an interesting display animal, especially when kept in groups (solitary individuals often do poorly in the aquarium).

Stenopodidae (Boxer Shrimps)

The boxer shrimps have large pincers on the third pair of legs and very long antennae. This family includes one of the most popular decapod species in the aquarium trade - the Banded Coral Shrimp (Stenopus hispidus). There are other species that enter the trade, but they do so less frequently. The boxer shrimps get their common name for their long chelae that are held apart in a pugilistic manner. They also have very long white antennae.

The boxer shrimps are usually found in crevices or caves, they often hang from ceilings. Some species regularly share their hiding places with moray eels, which the shrimps groom (they apparently feed on the eels' body slime and parasites). They may also clean other fishes, rubbing their long antennae against a potential client's body to induce posing. The Stenopus spp. are usually found in pairs and apparently form these bonds when they are quite small. The male is reported to do the foraging and will even bring food to its mate. Pair members have even been observed to defend their molting mates!

Although somewhat retiring, the boxer shrimps make great display animals. They are hardy, feeding on any food that hits the substrate. The aquarist should be aware that large boxer shrimps have been known to capture and kill small fishes (e.g., nano gobies). They will either grab them when they move past or catch them at night when these fishes are torpid. These are fast growing shrimps that molt frequently.

Most of the shrimps available to aquarists are relatively easy to keep if they are placed in the right captive venue. They should be provided with suitable shelter, but the type of shelter depends on the species in question. For example, most of the reef-dwelling forms simply need crevices or overhangs to lurk in or under. In contrast, most of the snapping shrimps encountered in the trade, prefer a sand bottom so that they can dig burrows. You can facilitate burrow construction by adding pieces of rubble or by placing flat rocks on the sand surface that act as a ceiling for their subterranean homes.

As indicated in our examination of the families encountered in the trade, there are certain shrimps that live commensally with specific invertebrate hosts. For example, there is a relatively large guild of shrimps that lives among the tentacles of sea anemones. While many of these anemone-dwellers may survive in an aquarium without a cnidarian, they are definitely more vulnerable to predators when not housed with their stinging host. Without their hosts, many of these species will hide incessantly and often perish prematurely. For example, I have had wholesalers send me the White-stripe Urchin Shrimp (Stegopontonia commensalis). This shrimp is like "a fish out of water" if it is not kept with sea urchins. It will hide among the rocks and typically will die soon after being placed in a tank that lacks an echinoderm host. The same can be said of the Emperor Shrimp (Periclimenes imperator), which is normally found riding on holothurians and sea slugs. It is dependent, at least in part, on the fecal material of its host, as well as other forms of detritus. When these animals are kept without their invert partner, they skulk about in reef recesses and are rarely seen or appreciated by the aquarist. To ensure that you provide your shrimp with the proper host, it is important to investigate the natural history of the animal that you are considering for your home aquarium before purchasing it. If you cannot provide these commensal forms with a suitable host, do not buy them.

Aquarium size is less of a factor for shrimps than it is for fishes. Most of the shrimps can be kept in tanks as small as 2 to 5 gallons. The majority of species available in the aquarium trade are quite small and do not need a large home range in which to roam. For example, many of the cleaner shrimps stay within the same crevice or cave for most of their lives. Some species are best displayed in smaller tanks. For example, a pair of Harlequin Shrimp in a 5 to 10 gallon tank makes a fantastic exhibit. If you place some of the smaller shrimps in a large reef aquarium, you may never see them again. They may hide constantly in the many caves and crevices present, or they may end-up being food for some cryptic predator (e.g., larger snapping shrimp, mantis shrimp) that came in with the live rock.

Feeding

Most of the shrimps will feed on any food that they can grab with their feeding appendages. This includes frozen preparations, brine shrimp, mysid shrimp, flake foods and tablet or pelletized foods. In the past, I have rarely target fed my shrimp. Instead, when I feed the fishes in the aquarium, I watch to make sure that some food makes it to the substrate where the shrimp hang-out. This may mean turning off the water pumps for a brief period so that food comes to rest on the aquarium bottom (don't forget to turn them back on after the shrimp get something to eat). If you are having difficulty getting food past your fish, you can use a turkey baster to squirt the food into caves and crevices occupied by your shrimp. The cleaner shrimps will supplement their diets with the slime, scales and possibly the parasites found on fishes in the aquarium. However, unlike many of the cleaner wrasses, these shrimps can live without this supplementary source of food (i.e., they can be kept in a tank without fishes).

When it comes to feeding, the highly specialized Harlequin Shrimps (Hymenocera spp.) are a notable exception to the rule. These shrimps only feed on sea stars and will need a ready supply of these echinoderms if they are going to survive in the aquarium. A medium-sized sea star should last a pair of Harlequin Shrimp about one week. Make sure you remove the uneaten portions of the sea star so that it does not pollute the aquarium. Many of the Bumblebee Shrimps (Gnathophyllum spp.) also have specialized diets. While echinoderm tube feet may be eaten in the wild, at least some of these shrimps will accept frozen food in captivity.

Shrimp Maladies

The shrimps are apparently not susceptible to many parasites or diseases. (However, it may be that we simply do not know enough about these animals to recognize when a shrimp perishes as a result of illness.) There are isopods that live in the gill chamber of certain shrimps. The most common of these appears as a swelling on the side of the carapace. Although it less commonly infects shrimps, fish lice (cymathoid isopods) have also been seen attached to shrimps. It is highly unlikely that these parasites actually kill their host, but they may weaken them.

Most of the shrimps available to hobbyists need relatively clean, well-oxygenated water. Shrimps tend to perish more readily during shipping if a shipment is delayed than other invertebrates or fishes because of oxygen deprivation. For example, the anemone shrimps in the family Palaemonidae are very sensitive to drops in oxygen levels and, as a result, often ship poorly. The aquarist should work quickly to acclimate these animals to holding aquariums so that they can be removed from shipping bags. Note that acclimation is very important for many shrimp species. If you expose them to drastic changes in temperature, oxygen levels, pH, or other water parameters, it is possible to shock them to death. "Drip acclimate" your shrimp for approximately one hour.

The exoskeleton of crustaceans is composed of chitin. In order to grow, crustaceans must periodically shed their exoskeleton. This process is known as molting. Before the old skeleton is shed, a new one is laid down beneath it. The old one splits open and the animal works its way out of the "shell." Calcium salts are extracted from the seawater and infused into the exoskeleton, which hardens the crustacean's armor. However, this takes time, so just after molting a crustacean is very vulnerable. As a result, they often spend more time hiding during this soft shell phase.

Unfortunately for crustaceans, there are predators that can smell chemicals produced during the molting process. Crabs and fishes will make short work of shrimps that have recently molted. (I once saw a large polychaete worm attack and swallow the chelae of a molting crab!) Not only is a molting shrimp more vulnerable to predators, it is also more vulnerable to attack from conspecific competitors. For example, boxer shrimps have been known to subdue conspecifics during or just after molting.

Occasionally, a shrimp will die during molting because of the increase in energy expenditure and oxygen deprivation. This can happen if the shrimp has a difficult time getting out of its old armor. If a shrimp is having a difficult time shedding the old exoskeleton from one of its appendages, it may lose the problem leg, claw or antennae. However, when it molts again, it will regenerate the missing limb.

Compatible Fish Tankmates

One of the most common causes of shrimp death are incompatible tankmates. Crustaceans are fed upon by many reef fishes and shrimps are some of the most delicate and vulnerable of all the crustaceans. Where a box crab or mantis shrimp may be able to thwart the attacks of predators with their large and/or modified forelimbs or heavy carapaces, most decapod shrimps are not as well equipped to ward off their piscine enemies.

Some shrimps are more susceptible to attack than others. For example, the boxer shrimps (Stenopus spp.) are larger in general and have more formidable pincers than the anemone shrimps (Periclimenes spp.). Many of the species in the latter group are small, delicate shrimps that associate with other animals as a form of self-defense. Therefore, if you add a boxer shrimp to a tank that contains a large shrimp goby, it is not likely to bother it. However, if you add a small anemone shrimp to this same tank, the goby may eat it.

When considering the potential danger they present to shrimps, fishes can be broken down into three major groups: those species that rarely if ever bother shrimps, those species that are potentially dangerous to shrimps, and those species that are always a threat to shrimp tankmates.

The members of the rarely if ever bother shrimps group are obviously the species that make the best decapod companions. This group includes the anthias, small cardinalfishes, angelfishes, butterflyfishes, most damselfishes, flasher wrasses, small fairy wrasses, tube blennies, combtooth blennies, dragonets, smaller gobies, dartfishes, surgeonfishes and rabbitfishes. These fishes can be classified as herbivores, sessile invertebrate feeders and microcarnivores.

The potentially dangerous to shrimps group is a mixed bag. These fishes tend to be more of a threat to smaller, more delicate shrimp species. Larger dottybacks, especially members of the genera Ogilbyina and Labracinus are dangerous to shrimps, while the smaller members of the pseudochromoid clan are usually not a threat to ornamental crustaceans. This applies to cardinalfishes as well. Larger apogonids are a threat to shrimps they can swallow whole, while the more diminutive cardinalfishes are usually good shrimp tankmates. Although many of the gobies are ideal shrimp tankmates, some of the larger species (e.g., Cryptocentrus) will ingest smaller shrimps. With members of this second group, adding the shrimp to the aquarium and letting it fully acclimate before you add the questionable fish species will help increase the shrimp's chances of survival. A stressed, flighty shrimp that has been dropped into a tank full of fish is a more attractive target than one that was there to begin with.

The fishes that are always a threat to shrimp include: the sharks, rays, morays, snake eels, coral catfishes, lizardfishes, toadfishes, frogfishes, squirrelfishes, scorpionfishes, waspfishes, groupers, comets, tilefishes, hawkfishes, snappers, goatfishes, larger wrasses, large jawfishes, sand perches, triggerfishes, puffers and porcupinefishes. The only species of shrimps that may survive in a tank with these fishes are the cleaner species. For example, if a cleaner shrimp species is introduced to an aquarium before a moray is added, the moray may "tolerate" the shrimp and not eat it. (I should point out, that keeping a cleaner shrimp with a moray makes for an amazing and educational display!)

Compatible Invertebrate Tankmates

Shrimps are not only vulnerable to being eaten by fishes, there are also a number of invertebrates that are a threat. Probably the most dangerous invertebrates are other crustaceans, especially crabs. Many crabs are omnivorous and opportunistic. If they can catch a shrimp, they will eat it. They use their powerful pincers to dismember their less heavily armored cousins. The only crabs I would trust with a prized shrimp are Porcelain Crabs (e.g., Anemone Crabs) and smaller hermit crabs. The voracious mantis shrimps are deadly to shrimp populations. They use their modified raptorial appendages to disable other shrimps.

Sea anemones are also potential shrimp predators. While there are some that can live among the stinging tentacles of these cnidarians, others will be stung and eaten. The Carpet Sea Anemones (Stichodactyla spp.) are the most dangerous. I have had cleaner (Lysmata spp.) and Marbled Shrimps (Saron spp.) dart about the aquarium and run into these toxic anemones when they were released into the tank. They were subdued and subsequently eaten. On one occasion, I had a large Clark's Anemonefish (Amphiprion clarkii) grab a marbled shrimp in its mouth and stuff it into its host carpet anemone! Some of the larger corallimorpharians, a close relative of the sea anemones, might also prey on shrimps. This includes the Elephant Ear Mushroom Anemone (Amplexidiscus fenestrafer) and some of the Rhodactis spp.

Many of the shrimps can be kept in pairs or in groups, while others are less tolerant of conspecifics, especially members of their own sex. For example, the Camel Shrimp is usually seen in large aggregations in the wild and can be housed in groups in the aquarium. Likewise, the Skunk Cleaner Shrimp (Lysmata amboinensis) is found in groups and will tolerate each other in the confines of the aquarium. But the related Blood Red Shrimp (Lysmata debelius) is more aggressive toward conspecifics and is best kept singly, or (a male-female pair can be housed together). The boxer shrimps (Stenopus spp.) can also be very aggressive toward members of their own kind. So, while these shrimps can be housed in male-female pairs (which are often available from LiveAquaria.com), they should not be kept with consexuals. Heterospecific Stenopus spp. are also likely to quarrel and may attack and kill smaller shrimps in smaller aquariums. Male Marbled (Saron spp.) and possible some of the larger hingebeak shrimps (Rhynchocinetes spp.) will spar, especially in tight confines. Fortunately, members of both of the latter genera are sexually dimorphic, with the males processing elongated chelae. Keep only one male of these species in the same tank, unless it is very large so that males may be able to avoid each other.

Shrimps in the Reef Aquarium

There are many shrimps that are welcome additions to the reef aquarium. Some of the best reef tank shrimps are members of the genus Lysmata, Periclimenes and Stenopus. There are some shrimps that can even be put to work in the reef aquarium. For example, the Atlantic Peppermint Shrimp (Lysmata wurdemanni) will graze on sea anemones in the genus Aiptasia. Populations of these anemones often grow out of control in the reef tank and will sting and damage the soft tissues of other sessile invertebrates. The snapping shrimp, as indicated above, can also be useful in helping stir sand substrate.

While some of the shrimps are wonderful reef tank inhabitants, others are best avoided. There are some species that will feed on corals and their relatives. The hingebeak shrimps will feed on mushroom anemones, zoanthids, leather corals, and possibly other soft coral species, while the members of the genus Saron have also been reported to graze on soft and stony coral polyps, mushroom anemones, zoanthids and tridacnid clams.

In conclusion, while the shrimps will not fit into every aquarium community, there are many species that are well-suited for either the fish or reef aquarium. Just remember to select their tankmates carefully and pick shrimps that will fit into your particular aquarium environment. Happy shrimp-keeping!

Scott Michael
Scott W. Michael is an internationally-recognized writer, underwater photographer, and marine biology researcher specializing in reef fishes, and was the Banquet Speaker at our 2007 and 2008 Coral Conference and Frag Swap. He is a regular contributor to Aquarium Fish Magazine, Freshwater and Marine Aquarium Magazine, SeaScope, and is the author of Reef Fishes Vol 1, Vol 2, and Vol 3, Vol 4, and Vol 5., A Pocket Expert Guide Marine Fishes, A Pocket Expert Guide to Reef Aquarium Fishes, 101 Best Saltwater Fishes: How to Choose and Keep Hardy, Brilliant, Fascinating Species That Will Thrive in Your Home Aquarium, Reef Sharks & Rays of the World, and Aquarium Sharks & Rays. Having studied marine biology at the University of Nebraska, Scott has served as a scientific consultant for National Geographic Explorer, the Discovery Channel, and French educational television.

Resources

Debelius, H. 1999. Crustacea Guide of the World. IKAN, Frankfurt, Germany, 321 Pp.

Fossa, S. A. and A. J. Nilsen. 2000. The Modern Reef Aquarium. Volume 3. Birgit Schmettkamp Verlag, Bornheim, Germany, 448 Pp.

Hoover, J. P. Hawaii's Sea Creatures. Mutual Publishing, Honolulu, Hawaii, 366 Pp.