© Johan Boshoff


Billfish [Istiophoridae]


Billfish can measure up to 6m in length.

Billfish Identification

The billfish has an elongated body and a long, hard dorsal fin which narrows towards the tail and folds into a groove. Its pelvic fins are narrow. The dorsal fin extends to form a crest which looks similar to a sail. Billfish have long snouts which look like a spear.

Billfish General Information

Billfish are a part of the Istiophoridae family which comprises of three genera and 11 species. They are differentiated from the swordfish which have a flattened bill, and no pelvic fins or jaw teeth. Billfish have long, thin pelvic fins, and its extended sail-like dorsal fin stretches to the tail. They are one of the fastest fish in the sea, hunting mid-ocean and using their bill to stun their prey. They are pelagic spawners and commonly referred to as ‘marlin spikes’ by sailors.

Billfish Feeding

Billfish feed on squid and fish.


They can be found in all tropical and temperate oceans across the world.

Common Species

Black marlin - Makaira indica
Blue marlin - Makaira mazara
Indo-Pacific sailfish - Istiophorus platypterus

© Johan Boshoff