The Orangelined Triggerfish (Balistapus undulatus), also known as the Undulate Triggerfish, Orange-lined Triggerfish, Orangetailed Triggerfish or Orange striped Triggerfish. Triggerfish obtain their name from the locking mechanism used to hold the dorsal spine in place. The main dorsal spine is kept erect by a second spine which locks the dorsal spine in place.
Only when this trigger spine is moved can the main spine be lowered. The spine is used for defensive purposes because when raised it makes it difficult for a larger predator to swallow them. The spine is also used to lock the fish into crevices or small spaces making it difficult for predators to extract them. Triggerfish are adept at sliding into small thin crevices and their dorsal spines are then erected to lock them into place.
ORANGELINED TRIGGERFISH APPEARANCE
The Orangelined Triggerfish has a typical Triggerfish shape, with its eyes set high on the body and far back from the mouth. This protects the eyes when dealing with urchins and some crustaceans. The skin is thick and leather like, also for protection from spiny and spikey prey. The relatively small mouth with strong teeth gives it a powerful bite.
The body is an overall blue green colour with yellow stripes which radiate out from the second dorsal fin. On the juveniles and females there are yellow lines on the face and on the very young juveniles there is a series of dots on the rear of the caudal area. In the caudal area there is either a black blotch or the lines are black rather than yellow. The caudal fin is yellow as are the spines of the anal and second dorsal fin. Full grown adult males can reach up to 30 cm in length.
ORANGELINED TRIGGERFISH IN THE WILD
The Orangelined Triggerfish is usually seen on reefs from 12 meters downwards and occasionally on walls. They seem to prefer areas with many hiding places and are adept at sliding sideways into crevices. Usually they are seen solitary and research in Okinawa on similar species indicated that a male would have a territory overlapping that of three females. Being highly territorial they will chase an intruder out of their territory.
Usually they are very shy fish and normally go into hiding at the sight of a diver. They are seldom seen far from a hiding spot and can fit into really tight places. Sometimes they will sit just outside their hiding spot and watch a diver and appear to be curious.
However when the female is guarding eggs the shyness disappears and I have had a female buzz me by swimming directly at my face a few times. When this occurs common sense dictates one should reverse away from them as they can probably deliver a painful bite.
Orangelined Triggerfish are found across the Indo west Pacific area from South Africa to Southern Japan, and the southern Great Barrier Reef.
ORANGELINED TRIGGERFISH DIET
Orangelined Triggerfish have a varied diet and feed on algae, sponges, crabs, bivalves, gastropods, algae, echinoids, tunicates, worms, eggs, and detritus. They are caught in some areas by fishermen using a relatively small hook baited with a whole prawn.
ORANGELINED TRIGGERFISH REPRODUCTION
Breeding with Triggerfish takes place between one male and a single female. The females lay their eggs on the substrate and they are fertilized by the male. The eggs are then guarded by the female to prevent them from being eaten by predators. While the female is guarding the eggs their behavior can be very aggressive.
ORANGELINED TRIGGERFISH AQUARIUMS
Although they are beautiful fish, they are not commonly kept in aquariums because of their size and territorial behavior. Beyond any question of a doubt they are not reef safe and great care has to be taken with their tank mates as they will likely attack most smaller fishes.
Many aquarists describe their behavior as mean so these fish are not for everyone and require a large tank which they will probably rearrange. They are however reportedly intelligent and curious fish that are very easy to feed. Because their teeth continue growing throughout their life they require hard shelled crustaceans on a regular basis to wear them down.
Because of their sharp teeth and propensity to bite great care should be taken with these fish and if the stories are correct several aquarists have been bitten by them.
Triggerfish are supposedly very good eating and are targeted by fishermen in some areas.