The adult ballan wrasse is found in the coastal zone, up to 20 metres in depth, around rocks, offshore reefs, and seaweed. Juveniles, on the other hand, prefer intertidal areas. All individuals are born females and, from the age of four to 14 years, some of them may convert into males. These are responsible for building the nests in rocky crevices and for guarding the eggs for a week or two, when the eggs hatch.
The seagrass meadows are amongst the most productive ecosystems of the Northern Atlantic. These are the only angiosperms adapted to underwater life in salt water. They cover extensive areas of bottoms of estuaries, lagoons and tropical and temperate coastal zones.