Platybelone argalus subsp. platyura. Needlefish are slender fish, in this sp. it can reach 50 cm long. They have a single dorsal fin, placed far back on the body, almost opposite to the anal fin. Their most distinctive feature is their long, narrow beak, which bears multiple sharp teeth. The keeltail needlefish's top jaw is also smaller than the lower one. It is most recognized by the large, flat keel-like structures running on either side of the tail. Usually seen just below the surface in shallow waters near the shoreline of Lankayan (Sabah, Borneo).
The keeltail needlefish, sometimes called the keeled needlefish, is a tropical fish of the family Belonidae. It was described by the French naturalist Charles Alexandre Lesueur in 1821.