Fish Identification Photos: Keeltail Needlefish, Platybelone argalus pterura: The Keeltail Needlefish has an exceedingly elongated very slender cylindrical flattened body that is dark green on top and silver on the sides and belly

A key to identification of the Keeltail Needlefish is that the tail base is flattened into a large keel that is at least three times wider than it is deep.

The Keeltail Needlefish has a long jaw. The lower jaw is normally longer than the top jaw. It has two red-brown lines on top of the back behind the eyes.

The caudal fin of the Keeltail Needlefish is forked with a slightly larger lower lobe. The anal and dorsal fins are without frontal lobes. The Keeltail Needlefish reaches a maximum of 16 inches long and is normally found in the first 15 feet of the water column.

Due the unique shape of its tail base the Keeltail Needlefish cannot be confused with any other needlefish. It is a coastal pelagic species that in Mexican waters is found along both coasts of the Baja California peninsula, south of San Quintin on the Pacific and south of Santa Rosalia in the Sea of Cortez. It is also present along the coast of the Mexican mainland from Acapulco south to Guatemala and around all of Mexico's oceanic islands.

The Keeltail Needlefish is a member of a group of coastal and oceanic pelagic schooling fish that are normally found on the surface well off shore that belong to the Belonidae Family which in Mexico are known as agujones.

Keeltail Needlefish, Platybelone argalus pterura: A rare contribution that showed up when one purchased a “scoop of bait” in August 2006. Caught in the surf zone, La Playita, San Jose del Cabo, Baja California Sur, Mexico, with a water temperature of 85 degrees, early morning in 5 to 10-foot deep water, utilizing a cast net by panguero bait salesmen. Size approximately 13 inches. Description and photo courtesy of John Snow.