Despite the name, Blakiston's Fish Owls eat more than fish. They also feed off of small mammals, waterfowl, crustaceans, and amphibians. The most common hunting tactic observed is dropping down on prey from a low perch. Small meals are brought back to a perch and consumed, while larger targets will be partially consumed on the spot.
Blakiston's Fish Owls mate for life, and each breeding pair inhabits a specific territory. They are believed to non-migratory over large distances, though they might make small, seasonally based movements.. They pair does not breed each year, and it is suspected that breeding is dictated by environmental factors. One or two eggs are laid at a time, and the female incubates while the male hunts and brings back food. After the eggs have hatched, both parents take turns hunting. Chicks fledge around 50 days.
Blakiston's Fish Owls are protected by the nations that they are native to, and there are a handful of captive breeding and release programs. A major problem in their conservation is that despite the fact that the birds are protected, their habitat is not. A national park has been proposed for part of their Russian range, but as of right now it is only a suggestion.