Claudio Contreras / Pederson cleaner shrimp (Periclimenes pedersoni), Cienaga de Zapata National Park, Matanzas Province, Cuba.

David Hall / Crimson anemone (Cribrinopsis fernaldi) with Candy-striped shrimps (Lebbeus grandimanus) living symbiotically. Browning Pass, Queen Charlotte Strait, British Columbia, Canada. September.

David Hall / Candy stripe shrimp (Lebbeus grandimanus), a commensal species that associates with crimson sea anemones. Browning Pass, Queen Charlotte Strait, British Columbia, Canada. September.

Alex Mustard / Reef lizardifsh (Synodus variegatus) at a cleaning station, being cleaned by Holthuis anemone shrimps (Ancylomenes holthuisi). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Shane Gross / Pelagic thresher shark (Alopias pelagicus) cleaned by a Bluestreak cleaner wrasse (Labroides dimidiatus) at Monad Shoal off Malapascua Island, Philippines.

Shane Gross / Pelagic thresher shark (Alopias pelagicus) being cleaned by a bluestreak cleaner wrasse (Labroides dimidiatus) at Monad Shoal off Malapascua Island, Philippines.

David Fleetham / Cleaner wrasse (Labroides dimidiatus) eating parasites off Coral grouper (Cephalopholis miniata) with Shrimp (Lysmata amboinensis) Mabul Island, Malaysia.

Alex Mustard / Harlequin sweetlips (Plectorhinchus chaetodonoides) cleaned by a pair of bluestreak cleaner wrasse (Labroides dimidiatus). South Atoll, Tubbataha Atolls, Tubbataha Reefs Natural Park, Palawan, Philipp...

Brandon Cole / Bluestriped fangblenny (Plagiotremus rhynorhynchus) in hole, Indonesia, tropical Pacific Ocean.

Alex Mustard,Alex Mustard / A portrait of a small Candy stripe shrimp (Lebbeus grandimanus) in front of its host pink anemone (out of focus because of the magnification). Browning Wall, Browning Pass, Port Hardy, Vancouver Islan...

Georgette Douwma / Dead surgeonfish being 'cleaned' by a Bleusreak cleaner wrasse (Labroides dimidiatus). Many fish observed dead or dying on reefs in the Maldives, April 2012. Another episode of dying fish was in 2007....

Alex Mustard / Pederson cleaner shrimp (Periclimenes pedersoni) cleaning the eye of a Nassau grouper (Epinephelus striatus), Bloody Bay Wall, Little Cayman, Cayman Islands. British West Indies, Caribbean Sea.

Alex Mustard / Glasseye snapper (Heteropriacanthus cruentatus) head portrait with a cleaning Goby (Gobiosoma genie) East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Petra Wegner / Cavalier King Charles Spaniel, tricolour, getting teeth brushed with oral cleaner, model released

Todd Mintz / Sharknose cleaner goby (Gobiosoma evelynae) pair sheltering in hard coral, Netherlands Island, Dutch Antillies, Caribbean

Brandon Cole / Four-foot long Goliath Grouper (Epinephelus itajara) being cleaned by cleaner gobies. Florida Keys National Marine Sanctuary, USA, Atlantic Ocean, July.

Juergen Freund / Yellowtail fusilier (Caesio cuning) being cleaned by a Bluestreak cleaner wrasse (Labroides dimidiatus) Papua New Guinea.

Juergen Freund / Giant manta ray (Manta birostris) at a cleaning station. North Raja Ampat, West Papua, Indonesia.

Juergen Freund / Giant manta ray (Manta birostris) at a cleaning station with diver swimming behind it. North Raja Ampat, West Papua, Indonesia.

Juergen Freund / Giant manta rays (Manta birostris) at a cleaning station. North Raja Ampat, West Papua, Indonesia.

Georgette Douwma / White banded/ Scarlet cleaner shrimp (Lysmata amboinensis) on Coral hind (Cephalopholis miniata) Rinca, Komodo National Park, Indonesia, October

Nick Upton / Rock cook / Small mouthed wrasse (Centrolabrus exoletus) caught in a rock pool on a low tide, being taken out of a fishing net. Cornwall, UK.

Georgette Douwma / Elongate surgeonfish (Acanthurus mata) at a cleaning station with Bluestreak cleaner wrasses and sweepers in the background. Andaman Sea, Thailand

Georgette Douwma / Red soldierfish (Myripristis murdjan) being cleaned by a Bluestreak cleaner wrasse (Labroides dimidiatus), Andaman Sea, Thailand

Georgette Douwma / Lyretail anthias or Goldie (Pseudanthias squamipinnes) male being cleaned by a Cleaner wrasse (Labroides dimidiates). Rinca, Indonesia

Doug Perrine / RF- Green sea turtle (Chelonia mydas) being cleaned by herbivorous cleaner fish species Yellow tangs (Zebrasoma flavescens) and Gold-ring surgeonfish (Ctenochaetus strigosus) that graze algae on turtl...

Brent Hedges / Yellow edged moray eel {Gymnothorax flavimarginatus} with cleaner wrasse. Milne Bay, Australia

Doug Perrine / Yellow edged moray eel {Gymnothorax flavimarginatus} having mouth cleaned by Humpback cleaner shrimp {Lysmata amboinensis} Sabah Borneo (Non-ex).

Constantinos Petrinos / Blue triggerfish {Pseudobalistes fuscus} with Cleaner fish Red Sea

Brandon Cole / Spotted cleaner shrimp {Periclimenes yucatanicus} amongst sea anemone tentacles, Dominica Caribbean Sea. NOT FOR SALE IN USA

Georgette Douwma / Giant moray eel with Cleaner wrasse {Gymnothorax javanicus} Red Sea

Brent Hedges / Giant moray eel with Cleaner wrasse fish{Gymnothorax javanicus} Papua New Guinea

Chris Newbert / Scarlet Cleaner Shrimp (Lysmata amboinensis) pair cleaning a Moray Eel (Gymnothorax ocellatus) 80 feet deep, Solomon Islands

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning mouth of Tomato Grouper (Cephalopholis sonnerati), Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning mouth of Tomato Grouper (Cephalopholis sonnerati), Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning female Stocky Anthias (Pseudanthias hypselosoma), Tulamben, Bali, Indonesia

Gary Bell/ Oceanwide / Whitemouth Moray (Gymnothorax meleagris) being cleaned by Cleaner Wrasse (Labroides sp) juvenile, Christmas Island, Australia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning Yellow-edged Moray (Gymnothorax flavimarginatus), Tulamben, Bali, Indonesia

Gary Bell/ Oceanwide / Scarlet Cleaner Shrimp (Lysmata amboinensis) cleaning Honeycomb Moray Eel (Gymnothorax favagineus), Tulamben, Bali, Indonesia

Fred Bavendam / Scarlet Cleaner Shrimp (Lysmata amboinensis) working on a Tomato Grouper (Cephalopholis sonnerati), Milne Bay, Papua New Guinea

Alex Mustard / Two male Bullethead parrotfish (Chlorurus sordidus), one with a Cave cleaner shrimp (Urocaridella sp) on its nose, sleeping in crevices in a coral reef at night. Sharm El Sheikh, Egypt, Red Sea.

Alex Mustard / Male Bullethead parrotfish (Chlorurus sordidus) with a Cave cleaner shrimp (Urocaridella sp.) on its head, sleeping in a crevice in a coral reef, at night, Sharm El Sheikh, Egypt, Red Sea.

Alex Mustard / Two Bluestreak cleaner wrasse (Labroides dimidiatus) attending to a large male Steephead parrotfish (Chlorurus strongylocephalus), Laamu Atoll, Maldives, Indian Ocean.

Tony Wu / Bluestreak cleaner wrasse (Labroides dimidiatus) cleaning and attending Slender grouper (Anyperodon leucogrammicus). Pacific ocean, Papua New Guinea.

David Fleetham / Goldsaddle goatfish (Parupeneus cyclostomus) with two Bluestreak cleaner wrasse (Labroides dimidiatus) swimming alongside, Yap, Federated States of Micronesia, Pacific Ocean.

David Fleetham / Sleek unicornfish (Naso hexacanthus) gathering at a cleaning station on a reef waiting for the attention of one Hawaiian cleaner wrasse (Labroides phthirophagus), Hawaii, Pacific Ocean.

David Fleetham / Pyramid butterflyfish (Hemitaurichthys polylepis), with dorsal fins flared, line up for the attention of an endemic Hawaiian cleaner wrasse (Labroides phthirophagus), Hawaii, Pacific Ocean.