The invention relates to a strake for a wind turbine tower. A strake 2 for a wind turbine tower 1 is disclosed, whereby the strake 2 is realized as a detachable strake to be mounted to a wind turbine tower 1 to reduce vortex induced vibrations. The strake 2 comprises an outer structure 7 and the outer structure defines three sides that are interconnected by three angles, so that the strake 2 comprises a mainly triangular shape in its cross-cut perpendicular to its longitudinal direction. The strake 2 comprises at least one element that comprises a contiguous cavity 8 that is filled with a fluid.