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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.

Cleaners & cleaning stations

  The mutualistic relationship between cleaner fishes and their clients is considered here, while that between CLEANER SHRIMPS and their clients is considered elsewhere.

Cleaner fishes

seahorse dive leader for BCCR photograph of cleaner wrasse at its station

"A neon goby sitting on a coral is a sure sign of a cleaning station. Here's one waiting for clients. But look who runs the shop next door!" - Turneffe Island, Belize 2000. Video courtesy Andy Stockbridge, Belize.

NOTE Gobiosoma oceanops

  photo collage of various Caribbean cleaner fishes
Principal cleaner-fishes in the Caribbean are gobies, juvenile Spanish hogfishes, and initial-phase bluehead wrasses. Sometimes, juveniles of other species such as French and grey angelfishes may also act as cleaners. Because all but gobies will eat other foods, they are known as facultative cleaners, while gobies themselves are, with a few exceptions, obligatory cleaners.
seahorse dive leader for BCCR photograph of a Spanish hogfish taken from a video

"If you want to see cleaner fishes in action, watch for unusual posturing by fishes. Here's a Spanish hogfish getting worked over by several gobies, which is interesting, because a Spanish hogfish is a cleaner itself, but only as a juvenile." - Little Cayman 2001

NOTE Bodianus rufus


photograph of a barracuda getting cleaned
Principal client-fishes of cleaners tend to be larger species such as barracudas...






Barracuda Sphyraena barracuda being attended
by cleaner gobies Elacatinus (Gobiosoma) sp. and
a juvenile Spanish hogfish Bodianus rufus 0.5X

  .photo collage of groupers and seabasses being cleaned
..groupers and seabasses...

photograph of stoplight parrotfish being cleaned...parrotfishes are also commonly cleaned...photograph of a princess parrotfish being cleaned





Terminal-phase princess parrotfish
Scarus taeniopterus gets cleaned by
juvenile bluehead wrasses
Thalassoma bifasciatum 0.2X



Stoplight parrotfish Sparisoma viride gets
cleaned by a juvenile bluehead wrasse
Thalassoma bifasciatum 0.2X


photograph of queen angelfish getting cleaned...angelfishes are cleaned...







Queen angelfish Holacanthus cilaris being cleaned
by a juvenile bluehead wrasse Thalassoma bifasciatus
(the fish above the angelfish's head) 0.3X

photograph of spadefishes getting cleaned...spadefishes are cleaned...







Atlantic spadefishes Chaetodipterus faber being
cleaned by several cleaner gobies Elacatinus sp. 0.4X


photograph of a lizardfish getting cleaned, courtesy Anne Dupont, Florida...and lizardfishes are cleaned,...







Bluestriped lizardfish Synodus saurus
with 2 cleaner gobies Elacatinus sp.,
one inside the lizarfish's mouth 0.7X
Photograph courtesy Anne Dupont, Florida


photograph of several sergeant-majors getting cleaned...but smaller fishes may be cleaned as well. Note in the photograph that a single cleaner fish has stopped several sergeant-majors in their tracks. These fishes are essentially in perpetual-motion, so it shows how willing are they to be cleaned, even by a single cleaner.





A group of sergeant-majors Abudefduf saxatilis is
being cleaned by what looks to be an initial-phase
bluehead wrasse Thalassoma bifasciatus 0.25X

seahorse dive leader for BCCR photograph of creole wrasses taken from a video

"Sometimes client fishes seem desperate for cleaning. Here's a whole gang of creole wrasses that suddenly need cleaning by a juvenile hogfish. See how they drop in. But there's too many and they simply overwhelm the hogfish's service." - Little Cayman 2001

NOTE Clepticus parrae

NOTE juvenile Spanish hogfish Bodianus rufus


photo composite showing proportion of cleanings of creole wrasses Clepticus parrae by several types of cleaner speciesThe eagerness of creole wrasses Clepticus parrae to be cleaned is further documented in a study in St. Croix where SCUBA researchers observe 4600 cleaning events by 3 cleaner fishes and one cleaner shrimp over a 6d period in late summer. Censuses were made at 10m intervals on two 100m transect lines along the 15 and 33m depth-contours. Of the total events, 88% involve creole wrasses, with the remaining 12% being split among 31 other client species. Of the 4156 cleaning sessions involving creole wrasses, cleaner gobies Gobiosoma evelynae account for 71%, juvenile Spanish hogfishes Bodianus rufus 25%, juvenile bluehead wrasses Thalassoma bifasciatum 4%, and cleaner shrimps Periclimenes pedersoni <0.1%. Of all cleaners, bluehead wrasses were the ones most commonly seen in the study area and the ones most likely to fall prey to carnivorous client fishes. Perhaps because of this, the wrasses mostly cleaned planktivorous and herbivorous fishes, while the cleaner gobies dealt more with the predatory fishes. The researchers made a few night excursions, but witnessed no cleaning events after sunset. Johnson & Ruben 1988 Envir Biol Fish 23 (3): 225.

NOTE as a base of operations, the researchers used the HYDROLAB facility, which was at that time sited in the Salt River Submarine Canyon, St. Croix. This was an underwater-habitat lived in full-time by the scientists, which allowed them to extend greatly their bottom time over a depth range of 15-30m. The unit was moved to St. Croix in 1977 and while there accommodated 80 such research missions over an 8yr period, after which it was decommissioned and displayed for a time at one of the Smithsonian museums in Washington. CLICK here for more on HYDROLAB


photograph of octopus courtesy Anne Dupont, Florida
Reef organisms other than fishes, such as sharks, turtles, and morays may also be cleaned . In St. Croix, cleaner fishes Elactinus sp. have been observed cleaning an octopus, even entering the octopuses siphon to do so. Johnson & Chase 1982 Copeia 3: 712. Photograph courtesy Anne Dupont, Florida.





Octopus sp. perhaps looking to be cleaned 1X


photograph of Octopus vulgaris being cleaned by a cleaner goby Elacatinus randalliA long way south of the Caribbean Sea off the northeast coast of Brazil, scientists from the State University of Campinas additionally report 2 instances of cleaner fishes (cleaner goby Elacatinus randalli and cleaner wrasse Thalassoma noronhanum) cleaning an octopus (O. vulgaris). In each case the octopus blanches and darkens during the cleaning process. Sazima et al. 2004 Coral Reefs 23: 484; photograph courtesy the authors.



Octopus vulgaris blanches during cleaning
session with goby Elacatinus randalli 0.2X


photograph of a reef runner fish Elegatis bipinnulata scratching itself against the rough skin of a grey reef shark Carchaarhinus amblyrhynchos in Hawai'iAnother unusual instance of cleaning behaviour is reported by scientists at the University of Hawai’i, something that SCUBA-divers in the Caribbean might watch out for. Here, a small rainbow runner reef fish Elagatis bipinnulata uses the rough skin of a grey reef shark Carcharhinus amblyrhynchos to scrape against, presumably like a killer whale along its rubbing rock, or a dog scratching itself against the bark of a tree. What is being removed if anything is not known; perhaps it just feels good. The authors comment that this is the only example known where the cleaner (the shark) does not benefit from the cleaning symbiosis. Papastamatiou et al 2007 Coral Reefs 26: 277; photograph courtesy the authors.



The authors note that the reef runner fish Elagatis bipinnulata is
swimming along the shark from back to front, presumably for maximum
scratching benefit from the shark's backward-facing placoid scales

seahorse dive leader for BCCR photograph of a blue tang getting cleaned

"Cleaner fishes often hang out in the same location, and some species are thought to be territorial. Doesn't look like they're competing much for the blue tang, though. Hmmm! Must be heaven for the tang...what good service!" - Little Cayman 2001

NOTE Acanthurus coeruleus

  photo collage of cleaner gobies at station
Cleaner fishes are usually territorial and occupy specific sites, such as at prominent coral heads, known as cleaning stations.

photograph of a pair of sharknose gobiesPair-bonding between males and females (monogamy) is found in a few reef-fish species as, for example, butterflyfishes and some cleaner fishes. In such cases it is usually associated with defense of a territory. Studies in Barbados on sharknose gobies show that although sexual pairing is the norm, males will often court other females in the presence of their own mates. Whiteman & Cote 2003 J Fish Biol 63: 724; see also Whiteman & Cote 2004 Biol Rev 79: 351.



A pair of sharknose gobies Elacatinus evelynae,
possibly monogamous, rest on a coral head 1X


QUIZ for "gobiphiles": what advantage is there for a male goby to have a permanent mate over being on its own? Consider the possibilities listed below then CLICK HERE for explanations. Ideas from Whitman & Cote 2003 Anim Behav 66: 281.

Parental care is better for the offspring.

It makes it easier to defend the cleaning-station territory.

Males are actually unable to obtain more than a single female.

Good cleaning-station habitat is scarce, so it makes sense to double up.

The population is sparse, so it's best to snag a permanent mate if and when you can.

High-quality mates are rare, so hold on to a good one if you can.

Client fishes are attracted to stations with more cleaners.

seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a black grouper taken from a video

"Watch for goofy fishes at cleaning stations, like this black grouper. Cleaners readily enter mouths and gills to clean dead skin, parasites and, apparently, also wounds." - Turneffe Island, Belize 2000

NOTE Mycteroperca bonaci


photograph of 2 parrotfishes posturing while being cleaned
Posturing in characteristic ways signifies the willingness of client-fishes to be cleaned. Whether the behaviour is genetically based or learned is not known.







An initial-phase stoplight parrotfish
Sparisoma viride and an initial-phase
princess parrotfish Scarus taeniopterus
get cleaned by a wrasse 0.1X


photograph of a blue tang with possible cleanersTo pose or not to pose? Studies in Barbados of gobies at their cleaning stations show that a would-be client fish has a better chance of being cleaned when it poses. No clear pattern exists to explain this, not in species of client fish, size, or in the number of repeat visits. Cote et al. 1998 J Fish Biol 53: 256.

Prospective client fishes that look aggressive, or otherwise have aberrant behaviour are less likely to be cleaned.


A blue tang Acanthurus coeruleus is followed by a host
of other fishes, including at least 2 initial-phase
bluehead wrasses perhaps looking to clean 0.25X

drawing of a blue tang receptive to being cleaned
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of an initial-phase stoplight parrotfish looking to be cleaned, taken from a video

"Well, maybe posing doesn't always help, because there has to be some cleaner around to see it. This juvenile stoplight parrotfish is ever so hopeful, and quite patient about being ignored. Maybe it's in the wrong spot, or all the cleaners are busy." - Little Cayman 2001

NOTE Sparisoma viride

  collage of photos and drawings of fishes with ectoparasites
What are the cleaner fishes actually doing? They are cleaning the client fishes of parasites, loose skin, and other edible matter. Studies in Puerto Rico show that over 70% of parrotfishes, wrasses, surgeonfishes, damselfishes, butterflyfishes, groupers, jack, squirrelfishes, and grunts carry ectoparasites. The parasites consist mostly of isopods, copepods (see accompanying photograph), and trematodes (a type of flatworm). Gut contents of cleaner gobies and juvenile bluehead wrasses may be 90% parasitic isopods, comprising up to 1500 in number. Losey 1974 Copeia No. 4: 960; see also Grutter 1996 Mar Ecol Progr Ser 130: 61.

photograph of a neon goby
To conclude this section, let's view a conversation between a French grunt and a neon goby:
Ideas from Arnal & Cote 1998 Anim Behav 55: 1429.

cartoon 1 conversation between a French grunt and a neon-goby cleaner fish cartoon 2 conversation between a French grunt and a neon-goby cleaner fish
cartoon 3 conversation between a French grunt and a neon-goby cleaner fish cartoon 4 conversation between a French grunt and a neon-goby cleaner fish
cartoon 5 conversation between a French grunt and a neon-goby cleaner fish cartoon 6 conversation between a French grunt and a neon-goby cleaner fish
cartoon 7 conversation between a French grunt and a neon-goby cleaner fish cartoon 8 conversation between a French grunt and a neon-goby cleaner fish
cartoon 9 conversation between a French grunt and a neon-goby cleaner fish cartoon 10 conversation between a French grunt and a neon-goby cleaner fish

photograph of two cleaner gobies Elacatinus evelynae resting on a coral headgraph comparing growth of cleaner gobies in different habitatsThe stability of cleaning symbioses on coral reefs requires mutual trust - trust by the client that the cleaner will not take bites of flesh along with the ectoparasitic crustaceans that the cleaner is supposed to removing, and trust by the cleaner that it will not be eaten by the client. Some cheating by the participants can be accommodated, but obviously only if it is significantly outweighed by “honest” behaviour. Of the two roles, cleaning is the more risky. Cleaners are small and openly advertise themselves; hence, are under risk of attracting the attention of predators. The major risk to clients in being cleaned is loss of foraging time. Can cost and benefit be assessed for a cleaner? Not for most species, but an exeption is the sharknose goby Elacatinus evelynae that is a facultative cleaner, sometimes occupying cleaning stations on coral heads, and other times sitting on barrel sponges where they rarely clean and feed mostly on nonparasitic copepods. A comparison of each strategy for immature Elacatinus in St. Croix shows, surprisingly, that growth rates are actually higher and mortality lower for individuals inhabiting sponges than for ones inhabiting cleaning stations. The authors of the study conclude that at some times and places, cleaning may actually be a sub-optimal strategy. White et al. 2007 Coral Reefs 26: 87.

NOTE clearly, more work is needed on this topic


photograph of cleaner wrasse Labroides dimidiatus cleaning a coral hind Cephalopholis miniataAs to why cleaner fishes don’t get eaten by their client fishes is a topic of great interest and one addressed in a study by a University of Queensland researcher on cleaner fishes Labroides dimidiatus and their client fishes, coral trout Plectropomus leopardus on the Great Barrier Reef. This cleaner species does a little “tactile dance” when confronting its client fish, and this dance is accentuated when the client fish is hungry than when it is satiated. The dance is sort of "touchy-feefy and may serve to ameliorate aggressive behaviour in the client fish. Unlike other potential client fishes, a coral trout will commonly eat its cleaner, and results show that an accentuated fluttery welcome appears to ease its predatory tendencies. The author is unclear how this might work (most importantly, how the cleaner is able to assess hunger level in the client), but considers it a kind of “preconflict management” strategy, allowing the cleaner to assess risk levels and take suitable steps to avoid what might be a “terminal” confrontation. No similar study appear to have been done on Caribbean cleaner/client relations. Grutter 2004 Curr Biol 14: 1080; photograph courtesy Norbert Wu Productions.

NOTE the author also tests parasite load on the client as a factor, but finds it not to be significant



Blue-streak cleaner wrasse Labroides dimidiatus cleaning,
in this case, a coral hind Cephalopholis miniata 1.2X


Along similar lines, researchers at the Bellairs Research Institute, Barbados compare levels of stress hormones cortisol in cleaning gobies Elacatinus evelynae before, during, and after cleaning sessions involving both predatory and non-predatory client fishes. What they find is that during a cleaner’s initial photograph showing cleaner goby Elacatinus evelynae cleaning a coney Cephalopholis fulvaassessment of the threat status of a client, a predatory species does elicit stronger stress symptoms than other non-predatory fishes. However, the cleaner’s response is neither to flee or freeze; rather, it approaches the client more quickly and cleans it more thoroughly than it would if it were a non-predatory species. The authors suggest that the strategy, by shortening the interval between initial contact and cleaning, may reduce potential stress. Soares et al. 2012 P Los ONE 7 (6):e39781. Photograph courtesy ABOUT FISH ONLINE.

NOTE two piscivorous species, graysby grouper Cephalopholis cruentata and spotted moray Gymnothorax moringa, are compared with two species that eat benthic invertebrates, French grunt Haemulon flavolineatum and whitespotted filefish Cantherhines macrocerus

This grumpy face might make anyone nervous: cleaning goby
Elacatinus evelynae
with a coney grouper Cephalopholis fulva

seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a yellowtail damselfish taken from a video

"I wonder if damselfishes ever get cleaned? I never see them at cleaning stations. Maybe they would spend all their time nipping the other customers." - Little Cayman 2003

NOTE yellowtail damselfish Microspathodon chrysurus

  photographs of Barbadian damselfishes
While studying the cleaning behaviour of gobies in Barbados, scientists observe that if cleaners station themselves within dusky-damselfish territories, frequency of visits from other client fishes was less and the main clients are, in fact, the damselfishes. The damselfishes chase off other would-be clients. Arnal & Cote 1998 Anim Behav 55: 1429; see also Whiteman et al. 2002 Coral Reefs 21: 245.
  Would it be a good thing for a damselfish to have its own personal cleaner? One would think so, but there are both pros and cons, as shown in the list below. Consider which may be good for the damselfish and which may be bad , then CLICK HERE.
more fishes to chase away means less time to forage eggs at risk of being eaten by other client fishes cleaning bouts may be shorter and less effective costs incurred in chasing off other client fishes

personalised cleaning service

no appointment needed answer box for damselfish quiz answer box for damselfish quiz

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