Discordipinna filamentosa was formally described by I-Shiung Chen et al in the journal Zootaxa from specimens collected in the deepwaters of Kumejima, Ryukyu Islands Japan. Formerly known as Discordipinna sp.1, the beautiful Discordipinna filamentosa is only the second member of the genus joining the little spikefin goby, Discordipinna griessingeri. Like its congener, Discordipinna filamentosa is super tiny, with the holotype barely over half an inch long, but what it lacks in size it makes up for with stunning coloration and fascinating behavior.
Although Discordipinna filamentosa is only now just getting a formal description, this rare nano goby has been known to Japanese divers and goby enthusiasts for nearly a decade, and there exists a rich catalog of pictures and videos of this species. However, whereas Discordipinna griessingeri is known to occur from the Red Sea to the Philippines, Discordipinna filamentosa is so far only known from Japan, in pretty deep habitats like the 82 meter (270 feet) depth where the holotype specimen was collected, so don’t expect to see this tiny treasure at your local fish store.