Triggerfish of Bunaken National Park
Around 40 species of fish make up the family Balistidae, or more commonly known as triggerfish. Almost all of them are reef dwelling fish, however there are a handful of pelagic species too – a couple of which can be found throughout Indonesia, although rarely spotted by divers or snorkellers.
Triggerfish vary in maximum size from as little at 20 centimetres fully grown, to as large as one metre, however the average size for most species is around 50 centimetres. They are one of most easily identified fish, with common traits found throughout the entire family.
They have a fairly compressed, diamond shaped body, with a large head that makes up roughly a third of their entire body size. They have extremely strong jaws, and their eyes (which often bulge out of their head, and can be moved independently of each other) are set unusually far back from the mouth, and very close to the top of their head. Most species are very colourful and tend to have distinctive markings, such as stripes, spots, or a combination of the both.
One of their most identifiable features is their fins and the way they swim.
Unlike most other fish – which use their caudal (tail) fin for swimming – triggerfish swim via balistiform locomotion, where they undulate their posterior and anal dorsal fins to move slowly and with great stability. When needed, they will use their caudal fin for a burst of speed.
They have two retractable dorsal spines. The anterior (first) spine can be locked in place by the second, and can only be unlocked by depressing the second, hence the name ‘trigger’ fish. These spines are used for protection, as when they sleep, they force their way into a crevice on the reef and lock their first spine so they cannot be pulled out by a predator. They also raise their anterior spines to warn off any potential threats.
Bunaken Marine Park is home to a number of triggerfish species – and below is a list of some of the more common encounters, but in no way is this list definitive.
