Abstract: Subsea heat exchanger (1) cooling a hydrocarbon-containing fluid by flowing seawater through it. Cooling pipes (4) are arranged in a convection section (11). The heat exchanger has an inlet (5a) and an outlet (5b) for the hydrocarbon-containing fluid, and an inlet (21) and outlet (22) for seawater. The seawater inlet (21) is connected to the cooling pipes (4). The inlet (5a) and the outlet (5b) of the hydrocarbon-containing fluid are connected to the convection section (11). The seawater can flow through the cooling pipes (4) and the hydrocarbon-containing fluid can flow in the convection section (11) in contact with the outer walls of the cooling pipes (4). The heat exchanger comprises also a cap (6) at at least one end of the cooling pipes (4), wherein the cap (6) comprises one or more receiving arrangements (8) for anodes (7) and/or one or more anodes (7).