The wrasses (Labridae) are a large family from the already large order of Perciformes. There are about 500 species of wrasses divided into about 70 genera. Their species richness is surpassed only by the gobies. Many species occur in schools on the coral reefs.
The wrasses’ colors and size and body shape vary so much that it is difficult to tell they are related. Juveniles and adults, as well as males and females, often look very different. Despite the variety, there are external characteristic features that make it clear that they are related. Most wrasses, just like the parrotfish, use only their pectoral fins for propulsion and use the tail part as a rudder. Although the mouth is not very developed, they have well-developed lips.
Some wrasses produce a cocoon of mucus at night. This layer probably protects the fish against certain parasites.
Some species of the genus Labroides also act as cleaner fish. Some wrasses, such as Thalassoma and Coris, spawn in open water, others, such as Labrus and Crenilabrus, build algal nests in the sand or between rock crevices. Those nests are guarded by the males, who then behave territorially. Within this group come species that can change sex. This is known from the cuckoo wrasse.
Other notable wrasse species include: common cleaner wrasse, rock wrasse, Oman wrasse, peacock wrasse, rainbow wrasse, redstripe wrasse and black eye wrasse.