| Odonus, Triggerfish, Lagoon triggerfish, Rhinecanthus, Orange‑lined triggerfish|
Odonus niger also known as the red-toothed triggerfish is a triggerfish of the tropical Indo-Pacific area, the sole member of its genus.
Redtoothed triggerfish Wikipedia
The redtoothed triggerfish is a dark, deep blue bodied fish, ranging up to 50 cm in length. The fins are all blue-green in color, having yellow and light blue trim. It has a lyre shaped caudal fin with a yellow bar between the lobes. Like all triggerfish redtoothed triggers have a retractable dorsal spine.
Their pectoral fins are quite small; as a result they steer mostly with their dorsal and anal fins, which makes them very maneuverable, and they also use these fins to move with an exotic type of propulsion reminiscent of a propellor. It is one of the most singular swimming styles in the ocean.
It inhabits open waters and current-swept seaward reefs between 0 and 35 metres (0–115 feet) and can often be seen in groups turning and circling just under the sea surface while feeding on plankton brought in by the current. Sponges are another part of their menu.
Odonus niger is a hardy member of a saltwater aquarium. It has a reputation as one of the most peaceful of the triggerfish. It is still however a triggerfish and can therefore not be easily kept in an aquarium with invertebrates, although careful selection of invertebrates sometimes can make it possible to keep in a reef aquarium. A single small Niger trigger can be kept in a 40-gallon aquarium, however because they are fast growing a larger tank should be strongly considered. For a full adult specimen a 200-gallon or larger aquarium is advised.