Also in this summer, as indeed in all the months of July and August in the Mediterranean Sea, we can witness what we have always considered a spectacle of nature and of the “Mare Nostrum“. That is the birth of the Chromis chromis or as we often say of the blue Mediterranean chromis. These little fish are truly to be admired thanks to their intense electric blue. Mediterranean chromis Chromis chromis Castagnole Blu intotheblue.it
To see them, however, you don’t need to be an expert diver, a mask and good fins are enough to dive close to holes, caves or simply ravines where there is shade, and in a very few meters of depth you can witness this spectacle of color that takes place in all summers.
Distribution and habitat
Mediterranean chromis,Chromis chromisor Damselfish is widespread in the Mediterranean (where it is very common) and in the eastern Atlantic between Portugal and the Gulf of Guinea (more rarely up to Angola).
It inhabits the shallow rocky bottoms where it lives in shoals scattered in mid-water. They are also found above the Posidonia oceanica meadows. The small specimens still with the blue livery are photophobic and are often encountered in caves, crevices and other shady environments.
It has an oval, flattened body, with a small mouth and large eyes. The dorsal fin is single, with spiny rays anteriorly and soft rays longer posteriorly, the anal fin has only two spiny rays followed by many soft ones. The caudal fin is notched in the center and has two pointed lobes. The upper and lower rays of this fin are darker than the rest giving the impression of a more incised tail than it actually is. The ventral fins and pectoral fins are quite developed. The scales are large.
The juveniles have an electric blue colouration, while the adult specimens gradually lose it as they grow to become dark brown or blackish with longitudinal rows of paler speckles on the sides. The coloring can vary: the males in care are very dark while at night the adults pale. It reaches a maximum length of 16 centimeters but is usually much smaller.
Reproduction and behavior
Reproduction takes place in summer, the male performs a nuptial dance to convince the female to go to the part of the seabed that will serve as a nest. There the deposition takes place for about 10 minutes after which the female is immediately chased away. The eggs are not floating but stick to the substrate thanks to the adhesive filaments they are equipped with and are actively defended and oxygenated by the male. During the day they swim in mid-water swarms, occasionally approaching the bottom to look for nourishment.