column spacer Symbioses
Mutualism hot buttons for symbiosis topics in BCCR hot button for commensalism part of B hot button for symbiosis quizzes part of BCCR hot button for mutualism part of BCCR hot button for parasitism part of BCCR
This part of symbioses deals with mutualism, while commensalism and parasitism are accessible via the icons. After viewing these 3 topics, you can test your knowlege by taking the symbiosis quizzes.

Cleaner shrimps

  The mutualistic relationship between cleaner shrimps and their clients is considered here, while that between CLEANER FISHES and their clients can be found elsewhere.
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of coral reef taken from a video

"Cleaner fishes work in the upper reef, while cleaner shrimps, like this Pederson shrimp, work on the lower part of the reef." - Turneffe Island, Belize. Video courtesy Andy Stockbridge, Belize.

NOTE Periclimenes pedersoni


photograph of cleaner shrimp Periclemenes yucatanicusphotograph of cleaner shrimp Periclimenes pedersoniPrincipal crustacean cleaners include several anemone-inhabiting shrimps, such as...



...and Periclimenes

  photo collage of banded coral-shrimps
...and banded coral shrimps Stenopus hispidus.
  photographs of banded coral-shrimps, one of them featuring a spotted moray being cleaned
While it is quite common on a dive to see cleaner fishes at work, it's less common to see cleaner shrimps actually cleaning. Mostly they just seem to hang out waiting for something to come by.

photograph of 2 Pederson shrimps finished cleaning a coney
In this photograph 2 Pederson shrimps are interrupted by the SCUBA-diver in their cleaning of a coney Epinehelus fulvus. The tentacles of the shrimp's host corkscrew-anemone can be seen as white dots lining the crevice on the Right.





Pederson shrimps Periclimenes pedersoni and
host sea-anemone Bartholomea annulata 0.25X


photograph of coney Epinephellus fulvus parasitised by a cymohoid isopod Anilocra haemuli

Coney Epinephellus fulvus parasitised by a
female cymothoid isopod Anilocra haemuli.
Photographed in an aquarium tank by the authors
In laboratory tests, Pederson cleaner shrimps are more adroit at removing isopod parasites from fishes than any other type of cleaner. French grunts are cleaned perfectly of juvenile cymothoid isopod parasites by Pederson cleaner shrimps, but not by several types of cleaning fish, or by banded or other cleaning shrimps. The researchers, from the University of Puerto Rico, note that theirs is the first study of its kind to show that Pederson cleaner shrimps Periclimenes pedersoni remove cymothoid isopods from client fishes (see photograph above). Bunkley-Williams & Williams 1998 Crustaceana 71 (8): 862. cartoon of a French grunt wanting a Pederson cleaner-shrimp to remove a load of parasitic isopods
  photo collage of cleaner shrimps Periclimenes spp.
Studies on behaviour of various cleaner-shrimps including 2 Caribbean species shows, surprisingly, that cleaning activities occupy less than 5% of the shrimps' daily time-budgets. Jonasson 1986 Diss Abstr Int Pt B: Sci Engin 47 No. 4: 141pp.  

photograph of cleaner shriimp Periclimenes yucatanicus with host corallimorpharian Actinotryx sp. in Panamaphotograph of cleaner shrimp Periclimenes rathbuni with host corallimorpharian Ricordea florida in BelizeWhile sea anemones of several species are the usual hosts for cleaner shrimps Periclimenes spp., the shrimps are sometimes found associating with various species of corallimorpharians. Whether this is just a local habitat accommodation or signifying a broader range of host preference than previously known will need further study. Ritson-Williams & Paul 2007 Coral Reefs 26: 147.

NOTE members of Order Corallimorpharia are close relatives of corals (O. Octocorallia), similar in morphology but lacking a stony skeleton

Cleaner shrimp Periclimenes rathbuni with host
corallimorpharian Ricordea florida in Belize 2X




Cleaner shrimp Periclimenes yucatanicus on host
corallimorpharian Actinotryx sp. in Panama. Although
the shrimp appears to be camouflaged, this is likely to be
just adventitious, as the role of colour in cleaner shrimps
is thought to be advertisement, not hiding 2X

seahorse dive leader for Biology of Caribbean Coral Reefs photograph of Pederson cleaner-shrimp on the reef taken from a video

"Pederson cleaner shrimps dance to attract a fish's attention and they're really quite fearless. I guess being bold goes with the business. Sometimes a diver's finger will get cleaned. A spotted cleaner is interested, but perhaps doesn't like the taste." - Bonaire 2003

NOTE Periclimenes pedersoni


Pederson and other cleaner shrimps lead doubly symbiotic lives, as they associate with various sea anemones as well as act as cleaners of fishes. Their bright colours openly advertise their presence while they move in and out of the protective tentacles of their host anemones.

Studies in Bonaire reveal that of 6 cleaner species examined (4 fishes and 2 shrimps), only Pederson cleaner shrimps Periclimenes pedersoni perform a photograph of Pederson cleaner-shrimp with its host anemonedisplay that could attract client fishes. Of 525 instances of cleaning, over 60% involve groupers, parrotfishes, brown chromises, and creole wrasses. Cleaning of bigger fishes such as groupers and parrotfishes is mainly by gobies (about 60%) and by P. pedersoni (28%). Queueing by fishes (in a line-up) occurs rarely (only 4 observations out of the 525 total); crowding of a cleaner fish such as by creole wrasses often takes the form of a tight, ball-like swarm, within which each client may be cleaned for only a few seconds. Cleaner shrimps such as P. pedersoni may initiate cleaning with touching or stroking with an antenna, possibly a recognition signal. Wicksten 1998 J Nat Hist 32: 13.

A Pederson cleaner-shrimp Periclimenes pedersoni is presumably
protected by the nematocysts of its host corkscrew-anemone
Bartholomea annulata
. The shrimp can be considered a commensal
if it does not affect its host in any way, or a mutual if the anemone
benefits. The type of symbiosis is actually unclear because we
don't know enough about the relationship of the two organisms 1.5X


The sea anemone Lebrunia danae contains symbiotic plant cells and may derive most or all of its nutrient and energy needs from their photosynthetic activity. It is also a popular host for several species of crustaceans, including cleaner shrimps Periclimenes pedersoni, P. yucatanicus, P. rathbunae, and P. americanus. Study of this anemone-crustacean assemblage in the Bahamas reveals 4 other crustacean participants, including a mysid shrimp Heteromysis photograph of sea anemone Lebrunia danae with cleaner shrimp Periclimenes pedersoni and an arrow crab Stenorhynchus seticornisactinae, a spider crab Mithrax commensalis, a shrimp Thor amboinensis, and the arrow crab Stenorhynchus seticornis. The authors refer to the grouping as an anemone-commensal assemblage, but their definition of this type of symbiosis differs from that used in BCCR. For example, as noted above, the Periclimenes species are more commonly considered to be mutuals, the arrow crab S. seticornis is thought to wander the reef without forming permanent relationships, and the other crustacean species may simply be sheltering beneath the protective shield of the anemone’s tentacles. Herrnkind et al. 1976 Bull Mar Sci 26 (1): 65. Photograph courtesy Dominique Marion & Dominique Sena, France dominique.marion.

NOTE this species has large highly toxic nematocysts and is painful to touch

NOTE the image in mind when reading this is sea anemones teeming with associated crustaceans; in fact, of 75 individual anemones examined, only 54 (72%) have any crustaceans at all, and each of these has just a mean of 1.2 crustaceans

A sea anemone Lebrunia danae with 2 "associates", a Pederson
cleaning shrimp and an arrow crab Stenorhynchus seticornis 1X


The foregoing study is unique in that it was conducted from HYDROLAB, one of the world's earliest "saturation-diving" habitats, set out in Grand Bahama Island in the early '70s for non-profit research activities. It stayed in place for several years at a depth of about 12m. Later it was moved to the U.S Virgin Islands until being decommisioned in 1985 and put on display in the Smithsonian Natural History Museum in Washington. The cylindrical habitat (8 x 16ft in size) had space for 5 divers, sleeping cots, equipment space, and a work table. Air, water, and electricity were provided from a surface vessel in continuous attendancl. Air pressure inside was a little more than 2atm or just enough to keep the ocean from coming in at 12m depth (note the open hatch in the photo). The advantage of saturation diving is basically 2-fold, the first being that you are literally a step away from your study habitats and have unlimited bottom time; the second, is that you can go deeper and stay longer with proportionaly less need for decompression than you would be able to do if starting from the surface. Once you are saturated with nitrogen, more time at 12m depth (measured in days, for example) would require no additional decompression time at the end of a session. After a study period of, say, a few days, a diver would photograph of HYDRO-LAB in Grand Bahama Islandpop (not literally) to the surface and enter a decompression chamber for the required decompression time. Unfortunately, the authors do not tell us how long they spent in the habitat (2-3d would be a reasonable guess), nor how they felt about the whole experience. The study, apart from its useful observations on Lebrunia, is an interesting glimpse into the history of North American underwater research. Provenance of the photograph is not known.

NOTE the authors use the quaint term "aquanauts" when describing divers working in and out of the habitat. However old-fashioned it may seem, the word is actually a good one, referring to individuals who remain underwater at ambient pressure for long enough to come into equilibrium with the external medium. The term may have originated with Jules Verne's Twenty thousand leagues under the sea written in 1870

The bottled gases visible here are likely for emergency use, but
the function of the background structure is unknown. There
must have been a system for waste disposal, but this may have
been done by a diver doing short-duration "bounce" ascents
to the surface vessel. The hatch would normally stay open
when the lab was in use, for divers to pop in and out, but
would likely beclosed during rough weather conditions


As for bettering our understanding of the cleaner-shrimp symbioses, let's "listen in" to this conversation between two spotted cleaner-shrimps sitting on their host sea-anemone:


photograph of a spotted cleaner-shrimp in its sea-anemone host

cartoon 1 of two spotted cleaner-shrimps discussing the function of their bright colorations
cartoon 2 of two spotted cleaner-shrimps discussing the function of their bright colorations
cartoon 3 of two spotted cleaner-shrimps discussing the function of their bright colorations cartoon 4 of two spotted cleaner-shrimps discussing the function of their bright colorations cartoon 5 of two spotted cleaner-shrimps discussing the function of their bright colorations
  photo collage of banded coral-shrimp cleaners
As noted earlier, unlike cleaner shrimps that live in association with sea anemones, banded coral-shrimps Stenopus hispidus roam throughout the reef and can be found in crevices, beneath overhangs, and inside the cavities of sponges. They are curious of SCUBA-divers, perhaps mistaking them for something that needs cleaning, and will move to investigate.

An interesting study in St. Thomas, US Virgin Islands assesses the feeding efficacy of 3 species of purported cleaner crustaceans, the Pederson shrimp Periclimenes pedersoni, the spotted shrimp P. yucatanicus, and the banded coral shrimp Stenopus hispidus on parasites found on blue-tang client fishes Acanthurus coeruleus. The results show, rather surprisingly, that of the 3 species tested, only Pederson shrimps were effective as cleaners, significantly modifying both size and number of parasites on blue tangs. In comparison, neither of the other shrimps had any long-term effect on parasite abundance. The authors remark that most previous accounts of the de-parasitising role of the shrimps in question may have erred because they were based on observations of the shrimps just crawling on or picking at the surfaces of fishes in small-scale aquarium conditions. According to the authors, the value of the their own study is in its long-term observation (3yr, summers) on behaviours in semi-natural situations. McCammon et al 2010 Coral Reefs 29:419.

NOTE the study is mainly conducted in a large semi-circular “mesocosm” tank at Coral World Ocean Park, St. Thomas

NOTE the parasites are flatworms Neobenedenia melleni, which is a common ectoparasite of reef fishes. Their activities include interference with mucus production, respiratory function of the gills, and other damage leading to secondary infections

  So, do these conclusions mostly negate our past thinking on the roles these shrimps play in cleaning? Let's not be so quick. Other knowledgeable scientists may have their own opinions. For what it is worth, a completely unscientific survey in Google Images reveals only 8 instances of blue tangs and other Caribbean surgeonfishes being cleaned, and all are being cleaned by cleaner fishes (juvenile Spanish hogfishes and angelfishes, gobies, and wrasses), none by cleaner shrimps. This is where you can help. If any diver/photographers have data on blue tangs being cleaned that could help in this matter, please communicate it to BCCR and we'll publish your observations here.

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