Marine Protected Areas and other managed marine sites are designated to improve the status of coastal fish assemblages and protect valuable habitats. The implementation of management practices relies on data collected through monitoring activities. The monitoring of fish assemblages using the standard non-destructive methods requires significant financial resources and time. A new approach to monitoring fish assemblages in the coastal waters was recently implemented in the Mediterranean – Fish Assemblage Survey Technique (FAST). It is based on Citizen Science where trained volunteer divers collect the data following a pre-established protocol. Considering the differences in species presence/absence and their sizes between the Mediterranean and the Adriatic Sea, a modification of the method was necessary. This study presents 23 main fish species and four ‘