Definitions for "Pelvic Fin"
Keywords:  fin, pectoral, ventral, underside, fish
These fins can be highly variable in their placement. They are usually on the underside of the fish between the pectoral and the anal fins.
paired fins (see Anatomy page).
one of the most posterior paired set of fins, in most livebearers located ventrally, just anterior to the anal fin. Used for stability in the water (helps keep the fish from rolling)