Purpose and audience This manual provides practical guidance for the planning, implementation, and evaluation of conservation translocations of native freshwater fishes in Greece and the wider Mediterranean region. It focuses on reintroductions and population reinforcement actions in lotic systems (rivers, streams and associated spring-fed habitats), with particular emphasis on species and populations that are threatened, declining, or locally extirpated. The procedures, tools and decision criteria presented here are tailored to the ecological, hydro-morphological and management realities of Mediterranean freshwater ecosystems, and especially to Greek inland waters. The manual is intended primarily for competent authorities responsible for water and biodiversity management (e.g. national ministries, river basin and regional water directorates, protected area management bodies), as well as for environmental agencies, NGOs and consultants involved in the design and delivery of freshwater fish conservation projects. It is also directed at researchers and technical experts who support these authorities through ecological assessments, feasibility studies, population modelling and monitoring programs. While the framework is designed with Greek legislation and governance structures in mind, most of the concepts, tools and recommended practices can be adapted and applied to similar conservation translocation projects elsewhere in the Mediterranean region.