Damselfish

Chromis chromis, the damselfish or Mediterranean chromis, is a small species of ray-finned fish of the family Pomacentridae from the Eastern Atlantic and Mediterranean.

Distribution

Chromis chromis occurs in the Black Sea, Mediterranean Sea and eastern Atlantic, from Portugal to Angola including the Macaronesian Islands and the Gulf of Guinea Islands, appearing to be commoner off islands than off the mainland. It is uncommon in the Black Sea and Sea of Marmara.

C. chromis inhabits littoral, mainly in rocky areas from 2 to 40 metres (6.6 to 131.2 ft) in depth, in small shoals in midwater above or near rocky reefs and above sea-grass meadows.

Behaviour

It feeds on small zooplankton and benthic algae. Its main food components are copepods, appendicularia, cladocera, gastropod larvae, bivalve larvae, fish eggs and fish larvae.

C. chromis feeding patterns are altered when schools are confronted with an increase in top water activity, resultantly, the species obtained a behavioral response referred to as polarizing. Polarization occurs when the species dives to deeper depths, leaving their food behind, as a mechanism to avoid confrontation.