Like every summers in the Mediterranean Sea, swimming in a few meters of water between rocks, rocks, holes and caves meet these beautiful fish of an intense electric blue. They are the fry of Chromis Cromis, commonly called Black Damselfish. Pesci Blu Blue Fish Chromis Chromis Castagnola Nera intotheblue.it
The young specimens are really a beautiful show, and it is really easy to swim among these small electric fluorescent blue fishes, because as soon as they realize they are not prey, they quietly approach the diver from all directions. It is not clear for which evolutionary strategy the little ones are of such an intense blue color, in fact once grown at the end of the summer the fluorescent blue livery disappears to become dark black. The fact is that they guarantee a unique spectacle of the Mediterranean sea that is always beautiful to see and photograph.
A curiosity of this species is that the reproduction takes place on rocky bottoms in holes and caves and is preceded by a particular ritual: the male performs a wedding dance to convince the female to go to the part of the bottom that will act as nest, there are also parental care turned to the egg, in fact after the deposition the female abandons the nest and the eggs are guarded by the male. The eggs are not floating but stick to the substrate thanks to the adhesive filaments of which they are equipped and are actively defended and oxygenated by the male. At hatching, the young have the characteristic electric blue color, while growing they gradually lose their color to become dark brown or blackish with longitudinal rows of lighter spots on the sides. Another curiosity is that at night the adults pale almost to become whitish.
Unfortunately also in this video the presence of man is clearly visible, while I approached in apnea to the hole of these splendid fishes we see a plastic and metal camping table completely stuck and partially concreted on the seabed, probably left abandoned on some beach and brought there by some storm and practically impossible to remove.