Spearfish can be distinguished from other billfish by a slender, lightweight body, short bill, and a dorsal fin that is higher than in marlin and lower than in the sailfish. The vent is located well in front of the anal fin; in all other billfish, the vent is located close to the anal fin. The bill of the shortbill spearfish is barely longer than its lower jaw. The pectoral fins of the shortbill barely reaches to the curve of the lateral line. The shortbill spearfish has 47 to 50 elements more in the first dorsal fin than any other Atlantic billfish, although it may appear similar to the white marlin. The lateral line is single and arches above the pectoral fins. The dorsal fin is bright blue and has no spots. The vertical bars on the body are never as prominent as in other billfish and may show only slightly or not at all.