A new species of polychaete, Parasphaerosyllis malimalii (Syllidae), inhabiting coral colonies of Pocillopora spp. was described on Coiba Island (Pacific coast of Panama) by Capa et al. (2001a). To improve its description and provide additional ecological remarks, 73 specimens of P. malimalii, found in dead fragments of Pocillopora spp. in two research projects on bioerosion in Gorgona Island (Colombian Pacific coast), between March 1998 and December 1999, and June 2015 and August 2018, were examined and measured. The average (±SD) length (in mm) of the specimens from the first (n=38) and second (n=35) projects were 2.84 (0.42) and 8.86 (3.24) respectively. The largest specimen was collected in the second project and measured 15.4 mm. The pygidium of this species has a pair of cirri slightly thicker and longer than the parapodial cirrus. These polychaetes are mostly dead coral inhabitants, nesting in vacant galleries left by borers. With this record, the distribution range of P. malimalii is extended southward to Gorgona Island. We are confident that this species must inhabit other coral reefs in the area, so we propose that the distribution of this species must be circumscribed to the Tropical Eastern Pacific.