Indo-Pacific Periclimenes Shrimp (An Overview)
Presented below is a brief overview of the various ornamental shrimps belonging to the genus Periclimenes that hail from the Indo-Pacific. Members of this genus are commonly referred to as “anemone shrimp”, although anemones are but one of a wide variety of other reef organisms that play host to these shrimp. Some of these host animals are too difficult for the average hobbyists to maintain in aquaria (e.g. Spanish dancer nudibranch) while others are simple enough to maintain in a ‘pico’-sized reef aquarium.
Click “read more” to, well, read more about the individual species…
Periclimenes colemani on a fire urchin: Here a pair of Coleman’s Shrimp are seen in their home, atop a venomous fire urchin (Asthenosoma varians). The shrimp gain protection within the urchin’s spines. You can notice that the small area around the shrimp is free from these spines. The shrimp work to pinch off these spines to create a protective nest around themselves. The diet of these shrimp consists of the soft tube-feet tentacles of the urchin on which they parasitize. The urchins do not seem to be negatively impacted by the predation and otherwise live normal lives while hosting the shrimp. The female is always larger than her male mate; the pair is monogamous.
Periclimenes soror on Linkia laevigata sea star: This species of Periclimenes shrimp lives exclusively on sea stars, hitching a ride on their protected undersides. The shrimp match their color to that of their sea star host. The shrimp keep the surfaces of the starfish clean by eating parasitic organisms, such as copepods, and dead tissue. What looks like a wart on the sea star in the bottom right of the picture is actually a parasitic gastropod Thyca crystallina.
The following pictures are all of the same species, Periclimenes imperator, but each displays a slightly different morphologic adaptation in both size and color depending on it’s host. P. imperator typically hitches a ride atop sea cucumbers or large nudibranchs (sea slugs). Their coloration is variable and matches that of its host. The shrimp gain protection and free transportation. As their hosts move along the sea floor, edible food particles are stirred up for the shrimp’s capture.
Periclimenes dardanicola on the anemone of an anemone hermit crab: A perfect example how the interconnectedness of the coral reef ecosystem can create extraordinary microhabitats. Here we see a small scene on the back of a hermit crab’s shell. The anemone hermit crab carries one or more anemones on it’s back for protection, and is active at night. The anemone gains feeding opportunities from the leftover scraps of the hermit crab’s meals. P. dardanicola not only takes advantage of these same food scraps, it also gains the protection of the anemone. The hermit crab, of course, is also dependent upon the empty shell of a dead snail which ultimately makes this whole micro community possible.
Periclimenes imperator on a leopard holothurian (sea cucumber) (Bohadschia argus): Here a small Periclimenes imperator crawls along the alien texture of a leopard holothurian. Like other types of sea cucumbers, the leopard holothurian is particularly noxious and unpalatable to would-be predators. As such, this soft-bodied echinoderm (Sea star family member) is able to sift through the substrate for organic matter on the open sea floor without hassle. This shrimp takes advantage of its host’s chemical defenses and gains access to any food particles disturbed by its foraging.
Periclimenes imperator on the back of a Spanish dancer nudibranch (Hexabranchus sanguineus): The Spanish dancer nudibranch is one of the largest of the sea slugs, reaching lengths of up to 40cm. They get their name from the graceful swimming movements it makes as it locomotes through the water column like an undulating magic carpet. Most of the time however, they spend their time like other nudibranchs on the sea floor moving like the slugs that they are. The blood red coloration is a warning sign to predators that the Spanish dancer is distasteful. Here we see the shrimp amongst the folds of tissue and frilly gills of the slug where it is gains protection. The shrimp will consume the slug’s fecal pellets and other organic debris that floats by.
The following three photos are of the same Periclimenes species, P. sarasvati, in a variety of anemone and coral hosts:
Many species of the genus Periclimenes are commensal with stinging cnidarians, particularly anemones, and act as cleaners for passing fish. Periclimenes sarasvati uses the tentacles of their hosts for protection, while gaining a platform upon which to perform its cleaning services. To signal that it is “open for business” the shrimp will float a few inches above its anemone home, and sway from side-to-side in mid-water, swinging its extra long antennae for added effect. Even large fish such as groupers and moray eels will come by these cleaning stations to have parasites removed, even allowing the shrimp access to their gills and inside their mouths (without ever eating them).
Periclimenes sarasvati in a bubble tip anemone (Entacmea quadricolor).
Periclimenes sarasvati in a Euphyllia glabrescens coral.
Periclimenes sarasvati in a Goniopora sp. coral.
Vir philippinensis in a Physogyra lichtensteini bubble coral: This close relative to the Periclimenes shrimp makes it’s home solely amongst the inflated vesicles of fleshy bubble corals. The shrimp can easily protect itself within these inflated vesicles, and cannot survive in any other coral species.
Periclimenes brevicarpalis on a pizza anemone (Cryptodendrum adhaesivum): This is another ‘cleaner’ species of Periclimenes shrimp. The lump on the left side of the shrimp is the female of an embedded parasitic copepod. The male copepod is minuscule in comparison and is permanently attached to her. The host shrimp seem to be able to lead a normal life with minimal detrimental impact despite this parasitism. The fluorescent coloration of the underside of the pizza anemone is seen here.
Periclimenes brevicarpalis on the surface of a Heterodactlya hemprichii anemone.
In a forthcoming segment, we’ll take a closer look at some of our Floridian species of Periclimenes anemone shrimp which make exceptional additions to the nano reef tank.