The ratfish, scientific name greenfin horseface triggerfish (file fish), also known as horseface fish, elephant skin fish, zizi color, tanner's knife, bread fish, burnt fish, skinned fish, goat fish, rat fish, Dizi, sand fierce.

The body is very laterally compressed and long oval. The head is triangular in lateral view, with the upper margin obliquely straight, and the muzzle long and pointed. The mouth is small and anterior. The upper and lower jaws have 2 and 1 rows of teeth respectively, incisor-like. Gill pores large, lateral. Scales minute, with several rows of small spines, borne directly on the substrate.

Two dorsal fins, the first dorsal fin with 2 fin spines, the first fin spine beginning above the pupil. Anal and second dorsal fins opposite, homomorphic. The two ventral fins are degenerate, synthesized into a short spine, attached to the end of the girdle, and immobile. Caudal fin rounded. Body blue-gray, second dorsal, anal and caudal fins green.

Eyes small, high, near dorsal margin. Gill pores small, located below the eye, scales fine and downy; body bluish gray, without lateral lines. First dorsal fin with 2 fin spines, first fin spine thick and with 3 rows of barbs; ventral fin reduced to a short spine attached to the end of the lumbar girdle bone and immovable, anal fin similar in shape to the second dorsal fin, beginning near the posterior anus; caudal peduncle long, caudal fin truncate, fin rays dark green.

Living in the bottom of the outer sea, inhabiting the water depth of 50 to 120 meters in the sea area. The temperature range is 13～20℃, with 14～17℃ as the optimal temperature. Like clusters, in the overwintering and spawning period there is obvious vertical movement phenomenon, generally floating during the day, sinking at night. Omnivorous, the main food copepods, isopods and mesopods and other planktonic crustaceans, mollusks and corals.

Before and after the spawning of large quantities of food, but in the spawning season is little or no food. During the day and night, it feeds mainly in the afternoon to the first half of the night, and less or no food in the second half of the night to the morning. The vertical movement of the greenfin leatherback is not only caused by the pursuit of bait organisms, but also related to its own habits.