A device, preferably a pump, for transport of fluid and biomass, preferably fish, comprising a rotating part and a house/casing enclosing the rotating part and a space between the rotating part and the house/casing forming a closed fluid volume with an inlet and an outlet for fluid and biomasses. Said space comprises a channel and said rotating part of single or double curved surface comprises circular cross- sectional surfaces, where said circular cross sections have increasing base diameter from said pump inlet at said upstream side of said pump to said pump outlet at said downstream side of said pump. A method for transport of biomass by means of a device following the steps: - connecting the inlet and outlet of the device to pipes to direct fluid and biomasses from a location to a desired location - at least placing the pipe leading from the inlet (41) of the device (10) in a location containing fluid and biomasses, preferably seawater or water and fish - at least placing the pipe leading from the outlet (42) of the device (10) to desired location of the transportation - starting a device for rotation (60), electric or hydraulic, preferably an electric motor connected to the rotating part (20) of the device (10) for rotating this part.
