The most recent Natel/Pacific Northwest National Laboratory test of 186 large rainbow trout measuring up to 500 mm (19. 7 inches) in length, found no meaningful difference between the fish passed through Natel’s 1.9 meter (roughly 6 feet) in diameter turbine and the control group, indicating that the RHT allows safe passage of some of the largest fish ever successfully passed through a compact hydro turbine.
Read Abe Schneider's opinion piece in The Ontario Waterpower Association's 2022 Year in Review about why Canada needs hydro turbines that are safe for fish to pass through.