Astronesthes richardsoni chin is ribbon-like and lacks a bulb or swelling at its tip. The dorsal fin has 12 to 14 soft rays and the anal fin has 13 to 18. The origin of the dorsal fin is behind the insertion of the pelvic fins. There is a dorsal adipose fin anterior to the caudal peduncle, and a small ventral adipose fin just anterior to the anus. There are two rows of photophores (luminous spots) on each side of the underside of the fish, numerous other photophores on the head and body and a luminous patch on the edge of the preoperculum;
Sessility (motility) organisms, in which individuals of a particular species group closely to one another for beneficial purposes, and can be seen in coral reefs and cochineal populations. This allows for faster reproduction and better protection from predators. The circa littoral zone of coastal environments and biomes are dominated by sessile organisms such as oysters. Carbonate platforms grow due to the buildup of skeletal remains of sessile organisms, usually microorganisms, which induce carbonate precipitation through their metabolism. In anatomy and botany, "sessility" refers to an organism or biological structure that has no "peduncle" or stalk. See Peduncle (anatomy), Peduncle (botany) and Sessility