The Syngnathiformes are an order of ray-finned fishes that includes the pipefishes and seahorses. These fishes have elongated, narrow, bodies surrounded by a series of bony rings, and small, tubular mouths. Several groups live among seaweed and swim with their bodies aligned vertically, to blend in with the stems. The name Syngnathiformes means "conjoined-jaws". It is derived from Ancient Greek syn (συν, "together") + gnathos (γνάθος, "jaw"). The ending for fish orders "-formes" is derived from Latin and indicates "of similar form".