Niger triggerfish or Odonus Niger is the sole member of its genus. Triggerfish are assigned to the family Balistidae. The niger is native to open waters and the reefs systems situated in the sifter current regions of the Indo-Pacific. Populations exist from southern Japan, down the entire east coast of Africa, ranging as far south as Australia.
Then name triggerfish is derived from the way spines on their dorsal fins move when they swim. The movement looks as if their dorsal fin is being triggered. These fish have the ability to make their dorsal fin erect when threatened. Erect fins serve the dual purpose of making the fish harder to swallow or to dislodge from a crack of crevice it has sought refuge in to avoid predation.
Triggerfish are among the marine species that possess teeth. One of the more unique characteristics specific to the niger is the color of their teeth or fangs as they are often referred to. These fangs have a distinctive reddish hue. This species is commonly sold under the names red-tooth or red-toothed triggerfish.
Do not be deceived by the niger triggerfish you see for sale in a fish store. These are juveniles. Adult nigers are one of the largest fish made commercially available by the aquarium industry. An adult can reach a length of 20 inches when fully grown. This is a narrow bodied oval shaped fish. Nigers are typically blue or purple in color. They have pale heads with deeper coloration on their bodies and a distinctive lyre shaped caudal fin. These fish make a grunting sound when they are excited or frightened.
There is a general rule of thumb when dealing with larger marine species. You should allow approximately 5 gallons of water for every inch of fish. This equates to a minimum tanks size of 100 gallons for a single adult niger. You must have a very large aquarium if you intend to keep this species as a community fish. They prefer brightly lit aquariums with high water flow. Providing them a place to hide in is highly recommended. They will perceive a dimly lit area with diminished water flow as a place to rest.
Triggerfish have a well deserved reputation of being aggressive animals. The niger is one of the most even tempered species of the group. They will get along fine with other fish that are of similar size and not exceedingly timid. If you intend to add one to your community tank it should be one of the smallest fish in the aquarium. Nigers will tolerate the presence of their own species provided they are introduced simultaneously to the aquarium as juveniles. In a marine reef they will probably nibble on your sponges but will leave your coral unmolested. This fish frequently lives in excess of 10 years.
Nigers are omnivorous. They have healthy appetites and will eat just about anything you throw their way including flake food and pellets. As with any marine species you will want to provide them with a varied diet. Flakes or pellets are an acceptable staple. Supplements can include vitamin enriched brine shrimp, frozen products developed for marine omnivores and finely chopped fresh seafood. Make sure they also get an adequate supply of plant matter to round out their diet. They will readily eat the same vegetables you serve for dinner. A note of precaution; this species has teeth. They have been known to bite the hand that feeds them. Although they are incapable of inflicting serious injury they can deliver a powerful enough bite to draw blood.