It inhabits open waters and current-swept seaward reefs between 0 to 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.
In the Aquarium 
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.
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