We report a new active asteroid in the main belt of asteroids between Mars and Jupiter . Object ( 62412 ) 2000 SY178 exhibited a tail in images collected during our survey for objects beyond the Kuiper Belt using the Dark Energy Camera ( DECam ) on the CTIO 4 meter telescope . We obtained broad-band colors of 62412 at the Magellan telescope , which along with 62412 ’ s low albedo suggest it is a C-type asteroid . 62412 ’ s orbital dynamics and color strongly correlate with the Hygiea family in the outer main belt , making it the first active asteroid known in this heavily populated family . We also find 62412 to have a very short rotation period of 3.33 \pm 0.01 hours from a double-peaked light curve with a maximum peak-to-peak amplitude of 0.45 \pm 0.01 magnitudes . We identify 62412 as the fastest known rotator of the Hygiea family and the nearby Themis family of similar composition , which contains several known main belt comets . The activity on 62412 was seen over 1 year after perihelion passage in its 5.6 year orbit . 62412 has the highest perihelion and one of the most circular orbits known for any active asteroid . The observed activity is probably linked to 62412 ’ s rapid rotation , which is near the critical period for break-up . The fast spin rate may also change the shape and shift material around 62412 ’ s surface , possibly exposing buried ice . Assuming 62412 is a strengthless rubble pile , we find the density of 62412 to be around 1500 kg m ^ { -3 } .