This species looks similar to, and is closely related to, G. marginatus, which is now understood to be not one species, but a cryptic species complex of four separate species that live in the Indian and Pacific Oceans. It share… 展开

At maturity, G. atlanticus is usually around 3 cm (1.2 in) in length, though larger specimens have been found. It can live up to a year under the right conditions. It is silvery grey on its dorsal side and dark and pale blue ventrall… 展开