the open structure of its mouth. The unexpected diet of Malacosteus is theorized to be a result of the small volumes that it searches for food, in which large prey items are rare. The rapid attenuation of red light in sea water gives Malacosteus a shorter visual range than species that use blue light, and it does not migrate vertically into more productive waters like other stomiids. Therefore, its strategy may be one of "snacking" on copepods, which are three orders of magnitude more abundant than fishes at its native depths, in between larger meals. The other factor believed to be partly responsible for Malacosteus''' diet is its unique visual system, which uses a derivative of chlorophyll as a photosensitizer that absorbs long-wave light (around 700 nm) and then indirectly stimulates the fish's two visual pigments, which have maximum absorbances at only 520 and 540 nm. No vertebrates are known to synthesize chlorophyll derivatives, and Malacosteus is believed to obtain these derivatives from the copepods it consumes. The red photophore of Malacosteus'' consists of a pigmented sac with a reflective inner lining and an internal mass of gland cells. Inside the gland cells, blue-green light is produced via the same chemical reaction found in other stomiids, which is then absorbed by a protein that fluoresces in a broad red band. This light is then reflected out through the photophore aperture, where it passes through a brown filter, yielding a far-red light with a maximum absorbance at 708 nm (almost infrared). In live fish, the suborbital and postorbital photophores both flash vigorously, the suborbital at a slower rate. References Stomiidae Deep sea fish Taxa named by William Orville Ayres Ray-finned fish genera