The Grey Wrasse (Symphodus cinereus) is a small fish of the Labridae family and in greek seas there are about twenty species that belong to the same family. However, the Grey Wrasse stands out for a behavior that, although often found among fish, in that case is particularly characteristic. Every year at the end of April the male begins to build a nest carrying small pebbles with his mouth. Within ten days the architect of the seabed constructs a cone-shaped nest with a perimeter that reaches almost half a meter. The nest has a top in order to be easily seen from afar while at one side the male lays seaweed and sticks creating something that looks like a"bed". Then the male acquires bright reproductive colours and develops an aggressive behavior towards each intruder, even if the intruder does not belong to the same species. Female Grey Wrasses quickly appear. Immediately the male demonstrates a robust dance that if the females like will then leave their eggs in the "bed". The male will then fertilize them and guard his little offsprings until these are old enough to leave their nest and the protection of their father.