The worldwide amphibian diversity is severely threatened, mainly due to deforestation. Lack of sufficient knowledge for species conservation is common. This is the first detailed study of the poison dart frog Excidobates mysteriosus including habitat requirements, occupancy patterns and behaviours. It is known only from one location in north-western Peru, living in Bromeliaceae plant species. The frogs and tadpoles were found in two unidentified Bromeliaceae species; Bromeliad Species 1 and Bromeliad Species 2. Bromeliad quality variables were evaluated for habitat requirements, behavioural recordings were performed ad libitum and catching-and-release with photographingof frogs for monitoring dispersals. Results show that for Bromeliad Species 1 significantly more frogs were present in bromeliads that were wider, received less sun exposure, had deeper water cavities and in bromeliads growing on lower altitudes. For Bromeliad Species 2 deeper water cavities had a significant effect on presence of frogs. In both bromeliad species higher presence of tadpoles were found in plants that were wider and had deeper water cavities. The density of bromeliads had no effect on frog or tadpole occupancy for neither bromeliad species. The dispersal, feeding and tadpole release behaviours are reported. Individual frogs were found to disperse 0-113m. The total number of encountered frogs was 1006 and 86 tadpoles, most of them found in three core areas. These areas should be targeted for conservation management and monitoring, diminishing the high deforestation pressure which saves old-growth forests and thereby as well the preferred wider bromeliads containing deeper water cavities and the biggest frog populations.