Yang (1999) revealed that fish home range is an essential factor to estimate theimportance of the coexistence of pools and rapids in river habitat. Minns' formula, which is defined for rivers and fish in North America, is one of the rare studies on fish home range. In this paper we examined the applicability of the formula to Japanese rivers and fish by using radio telemetry technique. We attacheda radio transmitter to dark chub, crucian carp, common carp, Japanese dace and pike gudgeon, and tracked their behavior in rivers. The observations support the importance of the coexistence of pools and rapids. Shelters during the flood periods are also indispensable for fish. Although they showed a similar home range size with Minns' formula during one to three days, they showed much larger home range for longer periods' observation. Usually they stay within Minns' home range but occasionally they trip a long distance to a nearby habitat.
