Silicon photomultipliers (SiPMs), thanks to their excellent performance, are becoming the photodetectors of choice for many applications. One major limitation, in particular for their use at high-luminosity colliders, is the radiation damage by hadrons. In this work, SiPMs with 4384 pixels of 15 × 15 μm 2 size produced by KETEK have been irradiated by reactor neutrons to six fluences up to Φ eq = 10 12 cm -2 (1 MeV equivalent neutrons). Pulse-height, IV, and CV measurements with and without illumination by a LED for temperatures between -30 and 30° C have been performed. In this paper results from the IV, and CV measurements are shown. The fluence and the temperature dependence of the current and of the SiPM electrical parameters like pixel capacitance, quenching resistance and breakdown voltage allows to better understand the origin of the dark current and find ways to reduce the radiation-induced dark-count-rate.