David Hall / Blue wrasse (Thalassoma lunare) in coral reef. Komodo, Indonesia.

Richard Robinson / Moon wrasse (Thalassoma lunare) juvenile at Yagasa Lagoon, Lau Island Group, Fiji.

Alex Mustard / Bluestreak cleaner wrasse (Labroides dimidiatus) sticking its head into the mouth of a Red Sea fusilier (Caesio lunaris) during a cleaning session. Small Crack, Sha'ab Mahmud, Sinai, Egypt. Red Se...

Matthew Maran / Snorkeller with Cresent wrasse (Thalassoma lunare), Koh Tao, Gulf of Thailand, Thailand, October 2013. Model released.

Pascal Kobeh / Several moon / Crescent wrasses (Thalassoma lunare) feeding on eggs lying on bottom probably laid by damselfish, coast of Dhofar and Hallaniyat islands, Oman. Arabian Sea.

Pascal Kobeh / Several moon / Crescent wrasses (Thalassoma lunare) feeding on eggs lying on bottom probably laid by damselfish, coast of Dhofar and Hallaniyat islands, Oman. Arabian Sea.

Doug Perrine / Reef manta ray (Manta alfredi formerly Manta birostris) with cephalic fins rolled up, being cleaned by Moon wrasses (Thalassoma lunare) and Blue-streak cleaner wrasses (Labroides dimidiatus) Hanifaru...

Doug Perrine / Reef manta ray (Manta alfredi formerly Manta birostris) being cleaned by Moon wrasses (Thalassoma lunare) and Blue-streak cleaner wrasses (Labroides dimidiatus) at mouth of Hanifaru Bay, Hanifaru Lago...

Doug Perrine / Reef manta ray (Manta alfredi formerly Manta birostris) being cleaned by Moon wrasses (Thalassoma lunare) and Blue-streak cleaner wrasses (Labroides dimidiatus) Hanifaru Bay entrance, Hanifaru Lagoon,...

Doug Perrine / Reef manta ray (Manta alfredi formerly Manta birostris) being cleaned by Moon wrasses (Thalassoma lunare), initial phase Two-tone wrasses (Thalassoma amblycephalum) and Blue-streak cleaner wrasses (...

Doug Perrine / Reef manta ray (Manta alfredi formerly Manta birostris) being cleaned by Moon wrasses (Thalassoma lunare) with cleaner fish inside open mouth, Sunshine Thila, Lankan, North Male Atoll, Maldives, India...

Fred Bavendam / Surge Wrasse (Thalassoma lutescens), New South Wales, Australia

Norbert Wu / Surge Wrasse (Thalassoma lutescens) hunts for food in sand, Seychelles

Norbert Wu / Moon Wrasse (Thalassoma lunare) terminal phase male and Pygmy Sweeper (Parapriacanthus ransonneti) in coral reef, Papua New Guinea

Tom Vierus / Mimic filefish (Paraluteres prionurus) and a Moon wrasse (Thalassoma lunare) swimming among a Sea fan, Vatu-i-Ra Conservation Park, between Viti Levu and Vanua Levu, Fiji, Pacific Ocean.

Russell Laman / Reef manta (Mobula alfredi) getting cleaned of parasites, dead skin, bacteria, and mucus by Blacklip butterflyfish (Chaetodon kleinii) and Moon wrasse (Thalassoma lunare) at a cleaning station in Raja...

Doug Perrine / Hawaiian cleaner wrasse (Labroides phthirophagus) cleaning a Raccoon butterflyfish (Chaetodon lunula), North Kona Coast, Hawaii Island, Pacific Ocean.

Doug Perrine / Two Raccoon butterflyfish (Chaetodon lunula) waiting to be cleaned of parasites by two approaching Hawaiian cleaner wrasses (Labroides phthirophagus), North Kona, Hawaii, Pacific Ocean.

David Fleetham / Raccoon butterflyfish (Chaetodon lunula), endemic Saddle wrasse (Thalassoma duperrey) and Sea urchin (Diadema sp.) on reef, Lanai, Hawaii, Pacific Ocean.

David Fleetham / Crescent wrasse (Thalassoma lunare) male swimming over reef. Pacific Ocean, Philippines.

David Fleetham / Saddle wrasse (Thalassoma duperrey) with schooling Raccoon butterflyfish (Chaetodon lunula) off the island of Lanai, Hawaii.

Sirachai Arunrugstichai / Healthy Staghorn corals (Acropora sp.) with various reef fishes, including Moon wrasses (Thalassoma lunare), and Threespot dascyllus (Dascyllus trimaculatus) and a large school of Bigeye snappers (Lut...