Alligator pipefish (Syngnathoides biaculeatus). X-ray of a section through alligator pipefish, showing their long snouts (left) and the numerous bony body rings that are used to differentiate one species of pipefish from another. Pipefish (family Syngnathinae) look like unfurled seahorses, which they are closely related to. The alligator pipefish is found in the shallow water of the tropical and subtropical Indo-Pacific. These specimens measure 18 centimetres in length.