Book excerpt: Syngnathids are a large and diverse group of fishes, including seahorses, pipefishes, seadragons and pipehorses, These iconic and vulnerable fishes are distributed worldwide in warm temperate to tropical environments, usually in coastal shallow water. Most species are marine and strongly associated with vegetal communities or coral reefs, which provide shelter and the necessary dietary resources. Syngnathids have a unique reproductive mode with parental care, diverse brooding structures and other special characteristics that make them highly vulnerable. These iconic fishes are facing several threats, namely environmental disturbances and habitat regression. However, many of their biological, ecological and physiological characteristics have been poorly investigated and limited to a few species. Despite their vulnerability, to date, a large number of species are listed as Data Deficient (meaning they could potentially be threatened) by IUCN due to inadequate or insufficient information, mainly on distribution and/or population status. Due to the progressive regression of wild populations, long-term monitoring programs are necessary to evaluate population dynamics, fisheries, and habitat quality. On the other hand, these charismatic fishes, especially seahorses, are excellent flagship species for marine biodiversity conservation. Unfortunately, illegal harvesting and traffic of seahorses and other syngnathids is a fact, despite CITES controls. Hence, the development of new tools for fish traceability and updated policies are also necessary to reduce the threats to these fishes.