PURPOSE: A device for managing river fishes and a method thereof are provided to confirm the movement and population of river fishes and to easily manage the river fishes. CONSTITUTION: A device for managing river fishes comprises an RFID tag(20) inserted in a fish, an RFID receiving unit(30) which is mounted in the river and recognize the information of the fish with the RFID tag, a collector(40) which comprises a wireless mobile communication terminal and collects the information of the RFID tag delivered through the RFID receiving unit, and a management server(50) which receives the information delivered through the collector and stores the information in database to manage fishes. The RFID receiving unit comprises a fixed housing, a perpendicular case, a sensor, and a reader. [Reference numerals] (22) Management number; (24) Intrinsic number; (30) RFID receiving unit; (40) Collector; (42) Wireless communication terminal; (50) Management server; (80) User's wireless communication terminal
