The Mediterranean Damselfish is one of the most common and recognisable fish along the region's rocky coasts. It is famous for the massive schools it forms and for the impressive colour change that occurs during its life. Young individuals possess a dazzling iridescent blue colour that makes them look like tropical neon fish. As they grow, the colour darkens, transforming into a deep brown or almost black hue that resembles the robes of monks. The body is oval and compressed laterally, with a characteristic forked tail resembling a pair of scissors.

This is a semi-pelagic species that lives close to the shore. It prefers clear waters with rocky seabeds and steep reefs, as well as Posidonia seagrass meadows. It is found at depths of 2 to 40 metres, where it swims in large, dense schools in the midwater layers just above the bottom.

This is a small-bodied fish species. The common length ranges from 8 to 12 centimetres, with a maximum of 15 centimetres.

The Mediterranean Damselfish is a planktivorous fish. It feeds primarily on zooplankton such as microscopic copepods and the larvae of other organisms, which it collects from the water column. It also feeds on other fish's eggs, which can affect the populations of different species.

Fisheries & Economic Value

The International Union for Conservation of Nature classifies the species as Least Concern because it is extremely abundant. Scientific studies describe it as a keystone species for Mediterranean ecosystems. Due to its large population, it plays a decisive role in the transfer of nutrients from the open sea to the seabed through its droppings, which fertilise rocky ecosystems. Furthermore, it serves as a primary food source for many larger predatory fish and seabirds.