The marine ornamental fishery (MOF), in which fish and invertebrates are harvested for the live aquarium trade, has been growing in the last years. It is a worldwide market where species are mainly harvested directly from coral reefs in tropical countries. In the island of Puerto Rico, in the US Caribbean, resource managers have little information about the impact of this harvest on the stock populations of the species in the trade. Due to concern about the potential for over-exploitation of the fishery, a regulation was passed in 2004 limiting the permitted species to be harvested and exported. This action caused significant conflict with ornamental fishers and exporters. In order to better manage the resource, more precise ecological and market information was needed, as well as a regulation that more accurately reflected the status of the resource. This study analyzed the marine ornamental trade in Puerto Rico, in order to provide baseline information and public policy recommendations. It evaluated management needs, enforcement, fishers' perspectives and practices, market forces, ecological assessment of the species, as well as explored a management tool for the commercial (edible species) fishery involving the ornamental trade. The findings of the study are split into two broad topics, a) socio-economics and b) ecology. a) The number of dedicated ornamental fishers on the island is quite small, possibly allowing for the trade to become a seasonal alternative to commercial fishers during closed seasons for edible species. Certifications that promote correct harvesting and handling of the species were found to be of interest to fishermen and managers. b) Reef surveys of fish and invertebrates around Puerto Rico found associations of fish species with habitat characteristics including depth and rugosity. Fish and invertebrate richness and abundance did not vary markedly between different sites and regions around the island, and no evidence could be detected of ornamental fishing impacts. It is suggested that more species of fish could be added to the permitted species list, without damaging their population densities. From both ecological and market perspectives, MOF in Puerto Rico is a viable and sustainable small industry that could be expanded to benefit local people and international traders alike.