The Niger Triggerfish is One Fish to Leave Out of your Reef Aquarium 

Niger triggerfish can make attractive additions to large saltwater aquariums, but when it comes to mixed reefs, and anything under 180 gallons, they are best left out. 

Also known as Redtooth triggerfish, Odonus niger is the sole member of its genus and is widespread from East Africa to the Red Sea, the Indian Ocean, Australia, Indonesia, Japan, and Pacific islands. In nature they congregate in groups, eating zooplankton, sponges, and benthic fauna, but in the aquarium, they eat a lot more including clean-up crew and even small fish, and there lies the problem.

Strictly speaking, Niger triggers are coral-safe. They’re often bought as two-inch juveniles, but they quickly grow to 6” subadults and rapidly increase in size, activity, and appetite. At six inches long artemia is not enough, and when they pace up and down, spit water out of rimless tanks, and savage any food that’s added (to the detriment of more timid species,) the first warning signs of trouble become apparent.

At two inches in length, they are relatively safe with mobile inverts too, like cleaner shrimp. But at six inches long, anything that’s added through the top of the tank is considered food and fair game, including cleaner shrimp, harlequin shrimp, emerald crabs, peppermint shrimp, and just about all the useful inverts you’ll need to add at some point throughout a reef tanks’ natural life. Then when they start taking chunks out of small fish, or your hand during maintenance, they are quickly returned to the store. 

Blue triggers aren’t out-and-out monsters like an Undulate triggerfish or a Queen trigger, but they do outgrow most tanks. They are 12”, heavy fish as adults, 18-20” long including fins and that means a lot of food going in, a lot of waste going out, and the need for much larger, more dedicated filtration than the average 75-gallon tank can provide. And they are super active. 

They get nicer as they mature too, developing a yellowish two-tone facial pattern, pinkish hues, long lyre tails, and those prominent red teeth. But if you saw an adult for sale in the store, or rather, adults were only available, you wouldn’t add them to your tank. Adult niger triggerfish are big, blue, beasts.  

Three Alternatives to the Niger Triggerfish

The Pinktail triggerfish, Melichthys vidua, is touted as reef-safe, but the most invert-safe triggerfish are those from the Xanthichthys genus. X auromarginatus, the Blue chin triggerfish, can be kept in sexed pairs and are beautiful when mature. Or the Sargassum triggerfish, Xanthichthys ringens, is a good option. But like so many other “reef-safe” fish, no trigger is truly reef-safe if you want security for every single invertebrate, large and small.

Main image credit Paul Korecky, CC BY-SA 2.0