Odonus niger: A Toothy but (usually) Nonviolent Trigger

Niger Triggerfish (Odonus niger) are also known as Redtoothed Triggerfish

Niger Triggerfish (Odonus niger) are also known as Redtoothed Triggerfish

Say “triggerfish” to a group of experienced salties, and you’re apt to evoke bloodcurdling memories of once-kept triggers massacring fellow fish, shredding sessile invertebrates, mangling submerged equipment, toppling rockwork, or even biting the hand that feeds them. Let’s face it, triggers don’t exactly have a reputation for stellar behavior in aquariums.

But not all triggerfish are rambunctious brutes! Odonus niger, the popular Niger or red-toothed trigger from the Indo-Pacific, is usually quite peaceful and well-mannered—by triggerfish standards, anyway. It’s also quite hardy, adaptable, and beautiful.

Physical characteristics

O. niger has the laterally compressed, vaguely football-shaped (American football, that is) body plan typical of triggers; an upturned mouth with protruding teeth; constantly fluttering dorsal and anal fins; a crescent-shaped tail that develops long, trailing extensions from each lobe; and a modified dorsal spine that can be locked in an erect position, allowing the trigger to wedge itself securely in reef crevices.

Ask me what color this fish is, and I’d have to say I really couldn’t tell you—and I have one! In most photos of the species, O. niger looks dark blue overall with a greenish face, but depending on the lighting and my position relative to the tank, my specimen can appear brownish blue, blue-green, purplish, or even solid black.

Piscine personality (pisconality?)

Like puffers, many of the triggerfishes, O.niger included, can become very pet-like, especially when they figure out you’re the source of their food. Mine often waggles at the front glass like an exuberant puppy to get my attention if I come into view but don’t approach the tank right away.

Don’t let that dog-like enthusiasm dupe you into hand-feeding this species, however. Those teeth mean business, and O. niger will bite (it is a trigger, after all!). Also, be very careful and know the location of your trigger any time you place your hands in the tank for cleaning, etc.


The Niger triggerfish does get large. The maximum potential size is over 19 inches, counting the aforementioned caudal fin extensions, though most captive specimens aren’t going to reach that prodigious length. Nonetheless, I wouldn’t recommend keeping one in anything smaller than a 125-gallon tank.


Niger triggers accept a wide range of fresh, frozen, and dry foods

Niger triggers accept a wide range of fresh, frozen, and dry foods

O. niger usually adapts to aquarium fare with little inducement and will accept a wide range of suitably sized fresh and frozen meaty foods as well as dry pellets. My specimen will even tear into the dried marine algae sheets I provide for my tang.

This species is, however, prone to hunger strikes when something is not to its liking for one reason or another. My specimen ate everything I offered with gusto right after I purchased it and placed it in quarantine. Then, for no reason I could discern, it stopped eating just as its four-week quarantine period ended and I was getting ready to transfer it to my display tank. No worries though! After a few days and some coaxing with fresh squid tentacles, it came back around and hasn’t stopped eating since.

Will O. niger play nice with tankmates?

Unlike many of the notoriously aggressive triggers, such as the undulate, queen, and clown triggers, the Niger trigger will tend to coexist peacefully with most moderately aggressive tankmates that are too large to eat. However, it’s very important to research potential tankmates carefully and to make sure you introduce them in the order of least aggressive to most aggressive.

Also, I would be remiss if I didn’t mention that despite the Niger trigger’s relatively peaceful reputation, it’s not unheard of for the occasional specimen to “go rogue” and turn on tankmates. Never let your guard down completely with this trigger in your community tank.

Generally speaking, the Niger trigger is reef safe, with the exception of small, motile invertebrates, but given its large size and commensurate waste production, I would not consider it the ideal choice for most reef systems.

Would you try a trigger?

So, what do you say, salties? Would you try keeping Odonus niger or another triggerfish? What experiences have you had—good or bad—with triggers? Let us know in the comments section below.


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About Jeff Kurtz

Jeff Kurtz is the Co-founder/Editor of Saltwater Smarts, former Senior Consulting Editor for Tropical Fish Hobbyist Magazine, and the aquarist formerly known as “The Salt Creep.” He has been an aquarium hobbyist for over 30 years and is an avid scuba diver.


  1. Kimberly Jin says

    In a reef tank, Odonus N Trigger is far more hardy than the Australian Harlequin Tusk any day.

    In my 10 years, all Harlequin Tusk I had in different tanks succumbed to white spots no matter how good my water quality was. It was just a matter of time in a reef tank.

    In my experiences, the Australian Harlequin Tusk does much better in a non reef tank.

    At the same time, I never lost any Odonus N or Long Nosed Butterfly or Blue Faced Angel of which have becomed my favorite fishes for recommendation.

    • Jeff Kurtz says

      Thanks for sharing these insights, Kimberly! O. niger definitely has a lot to recommend it!

    • I have a Aussie Harlequin Tusk and a Niger Triggerfish. Please email me with your # so that I may learn how to care for these fish, thanks!


    I really enjoy my triggerfish. I have a Niger, and a Huma Huma. Currently housed in a 75, but plans to upgrade to a 125, with 55 gallon sump/refugium. These fish have personality to spare. My Niger stopped eating a few days ago. He had been hiding in his rock a lot, and for lack of a better term….holding his mouth funny. Do triggerfish ‘TEETH”? I also have a medium Lunar Wrasse.

    • Jeff Kurtz says

      Hi Jerome! The niger trigger’s teeth grow continuously and, if not worn down with hard-shelled food items, can eventually grow to the point that they interfere with the specimen’s ability to eat (a point I probably should have made in my original post). It’s possible this is what’s happening with your specimen, though they can “go off feed” for any number of reasons.

      • Jonathan Morgenstern says

        How do you encourage them to whittle down their teeth?

        • Jeff Kurtz says

          Hi Jonathan! Crustaceans (of appropriate size for the specimen) with their exoskeleton still on, are a good choice, e.g. frozen plankton, krill, small shrimps. You can also try cracking open small clams or other bivalves so the trigger has to pick or rasp the meat from the partially opened shell. Just be sure to remove any uneaten portion promptly to avoid fouling the water.

  3. Jonathan Morgenstern says

    I was going to get one of these but now I’m thinking differently. Does anybody have a niger triggerfish?

  4. I used to have a beautiful 7 inch niger trigger fish. Ever since I got rid of him I have regretted it. He was very peaceful by trigger fish standards but I decided to get rid of him instead of getting a bigger tank. Bad choice, but a learning experience I guess

  5. brian fone says

    I have my niger with a scarlet hawkfish and a valentini puffer along with some high fins and fire gobies. He has a great personality and like the puffer acts like a puppy dog whenever he see’s me.Lots of fun and easy to take care of. Like the puffer his teeth tend to get to long sometimes. To solve this I put in some red legged hermit crabs from time to time. I usually lose the crabs but there constant pecking at the crabs whittles down their teeth quite nicely. I have a spotted puffer in a different tank that I literally had to file down his teeth with a jewelers file, as his teeth had become locked.. Then someone told me about the hermit crabs and his teeth have been fine ever since. I tried clams but they did not work. I think the constant motion of the hermit crabs keep the fish more engaged and they tend to peck at them more. It may be considered cruel to the crabs , But is better than losing some of my favorite fish. And believe me filing down a puffers teeth with a jewelers file is no easy task. Its been three years now and he is still doing Great.

  6. I just purchased a tiny Niger. He’s (she?) about the size of a US Quarter. I’ve been doing Marine tanks for better than a decade and this is my first trigger. I’m very excited about it.
    I’m looking for the best conditions to keep him for his entire life span. I’ve seen minimum tank size as low as 55g up to 180 gallon. Some say reef safe. Some say absolutely not. I have no intention of adding him to my reef. Probably be a FOWLR.
    How well do they do solo? Are they more social with tank mates or looking to have them for dinner?

    • brian fone says

      They do well solo. Nigers are one of the more docile triggers. They can have tank mates as well, Especially if they are smaller when introduced to fellow fish. I have mine in a 75 gallon tank along with a 18 year old Scarlet Hawkfish, A Saddle puffer 2 cardinals 2 Purple Gobies and A 12 year old Peppermint Shrimp. I introduced him 2 yeas ago and he was the smallest, Now he is by far the biggest. The key is to keep him well fed. If you are feeding lg. amounts once a day you might want to feed smaller amounts 2 or three times a day. They are hardy fish with a GREAT personality. Mine interacts with all the other fish in a playfull not malicious way. He and the Puffer are very good friends and can be seen riding the currents and just hanging out in general most of the time. I do not like to keep fish solo as I truly believe they become lonely without interaction. Try him with tankmates first, If he becomes aggresive then you can isolate him. Good Luck and Enjoy Brian

  7. I have a 150 gallon saltwater tank. I am thinking of adding a skoal(6-8) of green chromis to my tank. Currently I have 2 clownfish, 1 yellow tang, 1 hawkfish, 1 dwarf flame angelfish, 1 damsel, and 1 odonis niger trigger fish. Do you think it would be safe to add the green chromis? The trigger seems to be the most aggressive at feeding time. My concern is that the trigger may eat them since they are so small? Currently they all seem to get along fine. What are your thoughts? I look forward to your thoughts, Thanks!


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