The lagoon triggerfish (Rhinecanthus aculeatus), also known as the blackbar triggerfish, the Picasso triggerfish, or the Picassofish, is a triggerfish, up to in length, found on reefs in the Indo-Pacific region.
This species has been studied in a range of research contexts, from locomotion to color vision research.
Behavior
Lagoon triggerfish live in the reefs and sandy areas of coral reefs, where they eat just about anything that comes along, mostly including invertebrates and reef algae. They are always restlessly swimming around and vigorously protect their territory against intruders, including divers, especially when guarding their eggs during reproduction season. Their relatively small size makes them much less dangerous than the larger titan triggerfish of the same family.
The fish moves through the water by using waving motions in its dorsal and anal fins, allowing it to move more precisely. Using these movements, it can move forwards, backwards or simply hover in place above the reef. This means that it can more easily back out of crevices than other unidirectional fish.
Mating and reproduction
Both sexes guard territories, some maintaining a territory for eight years or longer (with males holding territories for significantly longer than females). A typical male territory may overlap with one to five female territories, and their mating system is described as haremic, although not much is known about this (similar mating systems are seen in other Balistidae species). If a male or female is removed or disappears their territories are soon taken over by a new fish. They reproduce multiple times over their lifetimes.
Vision
This species has one type of single cone (SC), with an opsin peaking in sensitivity at 413 nm (S), and a double cone with two different opsins in each member peaking at 480 nm (M) and 530 nm (L) respectively. Behavioural research has provided evidence that individual members of the double cones can act as independent channels of colour information, aiding in understanding double cone function. This research suggests the species has trichromatic vision, like humans.
<gallery mode="packed" heights="140">
File:Picasso triggerfish.jpg|Lagoon triggerfish live on the flat areas of the reef.
File:Picasso triggerfish Pengo.jpg|Aquarium specimen
</gallery>
See also
- Reef triggerfish