AppearanceIt is the smallest bream, with a record of 24 cm, and an average, depending on the zones, of 13-16 cm.
The mouth, relatively ample and protractile, has symmetrical jaws with 8 incisors followed by several rows of molars, for removing and chewing the small creatures living on the submerged rocks.
The dorsal fin is unique, formed by 11 spiny rays and 12-13 soft; the anal, about half long, contents of 3 spiny rays and 12-13 unarmed; the small ventral ones have one spine and the pectoral are long and pointed. The tail is forked.
The colour, bright silvery with a slight tendency to the yellow, gets more intense in the adults and reinforces with mimetic vertical dark bands when the animal is menaced.
In any case, the ventral and the anal fins are always more or less yellowish and even orange, but the most characteristic element, as mentioned before, is the black spot not edged of white towards the caudal peduncle.
Max. reported age: 7 years.
NamingThe name of the genus comes from the Greek “diplous” = two, and “odous” = tooth, therefore “double tooth”, with reference to the double incisors, particularly evident.
The name of the species comes from the Latin “annulus” = ring, due to the typical black annular spot just before the caudal peduncle, which is not, however, edged of white as is the case of the Saddle bream (Oblada melanura).
DistributionEastern Atlantic: Canary islands, also found along the coast of Portugal northward to the Bay of Biscay, Mediterranean, Black Sea and Sea of Azov.
StatusIUCN: Least Concern.
HabitatMarine; brackish; benthopelagic; depth range 0 - 90 m. Inhabit chiefly Zostera seagrass beds but also found on Posidonia beds and sandy bottoms, rarely on rocky bottoms.
ReproductionThe sexes are separated, although these fish are potential hermaphrodites; certain individuals are protandric. Normally sexes are separate but some individuals are protandrous due to geographical variation in sexual pattern. However, histological studies confirm no degenerating functional tissue of one sex (e.g. vitellogenic or later-stage follicles) and no proliferation of tissue of the other sex can be found on this species indicating the absence of sex change. This particular condition is also known as nonfunctional hermaphroditism previously known as rudimentary hermaphroditism.
FoodCarnivorous, feed on worms, crustaceans, mollusks, echinoderms and hydrozoans.
Some text fragments are auto parsed from Wikipedia.http://www.marinespecies.org/aphia.php?p=taxdetails&id=127049