Blackeye goby

Blackeye gobies can easily be identified by the fleshy crest on the upper surface of their heads, the distinctive black upper anterior edge of the first dorsal fin, their large scales, and large, dark eyes. They are small fish, reaching a maximum length of only 15 cm (6 in). The body is elongated, slightly compressed, and almost completely covered by scales. The head lacks scales and is wider than it is deep, with a small terminal mouth and a projecting lower jaw. The maxilla does not extend below the anterior margin of the eye. The teeth are conical and are present in double rows on both jaws. The eyes are directed slightly upwards and sideways. The dorsal fins are close together, with the first dorsal fin having five to seven rays and the second having 12 to 15. The pectoral fins have 21 to 24 rays, all of which are rigid. The anal fin has 11 to 14 rays with no spines. It is about the same size as the second dorsal fin. The caudal fin is rounded with about 17 rays, 12 of which are segmented and branched. The pelvic fins are completely fused with each other, forming a disk, each with four rays. These function as suckers. Coloration can vary, as blackeye gobies are capable of rapidly changing color during social interactions and for camouflage. The basic body color is creamy white to pale tan, but can become a mottled dark purple-brown. The body is irregularly speckled with metallic blue-green. Below the eye is an iridescent bluish spot clearly visible if illuminated (the source of their other common name – bluespot goby). The first dorsal fin has a distinctive black upper anterior edge that is retained even when the fish changes color. During breeding season, the pelvic fins of the males (normally gray in both sexes) turn jet black.