 The median and pelvic fins are brown, the pectorals are dusky, and sometimes there's a well-defined dark brown or blackish spot at the base of the posteriormost dorsal rays, which distinguishes it from the "S. lividus", where the spot is diffuse.When males are in courtship or guarding their eggs they have a broad white bar across the middle of the body and a pale blue stripe from the mouth to the upper part of the pectoral fin.