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Related FAQs: Red Sea Triggers, Triggerfishes in General, Triggerfish: Identification, Selection, Selection 2, Compatibility, Behavior, Systems, Feeding, Diseases, Triggerfish Health 2, Reproduction,

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/A Diversity of Aquatic Life

Rating the Triggerfishes of the Red Sea

Bob Fenner

 Rhinecanthus assasi

Triggerfishes for  Marine Aquariums
Diversity, Selection & Care

New eBook on Amazon: Available here
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by Robert (Bob) Fenner

The Triggerfishes are one of the most readily identified, best known and least understood of marine fishes. Their status as bad boys is not altogether undeserved; trigger big-headed and toothiness is all too obvious. As far as behavior, each species and individual must be considered with cynicism; "will or won't this swimming biting machine turn on it's tank-mates?"

Triggers as a whole don't deserve our avoidance; in particular the ones that are more and more available out of the Red Sea. Even if not endemic (only found there) these specimens tend to be more mellow, and are more colorful than their con-specifics of the broader Indo-Pacific.


The family of Triggerfishes, Balistidae, are mainly an assemblage of shallow water marine fishes, Atlantic, Indian and Pacific Oceans, of about 40 described species. Balistids are characterized by laterally compressed, ovate bodies, lack pelvic fins, have a first dorsal spine with locking mechanism (the second smaller spine making up the actual "lock"). Taking a look at their mouths, the upper jaw is not protractile, and bears two rows of protruding incisor like teeth. The fins they and their relatives the puffers use for locomotion, the soft dorsal and anal fins each have 25-50 rays. What can seem really buggy, their eyes can be independently rotated.

Red Sea Trigger Species:

There are thirteen species of triggers reported for the Red Sea area, only one of which is endemic. They are:

Abalistes stellatus, the Starry Triggerfish.

Balistoides viridescens, the Titan Trigger; well-named for it's size, over two feet. Canthidermis maculatus, the Rough or Spotted Trigger. Juvenile in an aquarium

Melichthys indicus, the Indian Trigger.

Pseudobalistes flavimarginatus, Yellow Face Trigger. Pseudobalistes fuscus, Blue Trigger. Juvenile in an aquarium

Pseudobalistes fuscus, Blue Trigger. A 2'er.

Balistapus undulatus, the Undulated Trigger. Balistapus undulatus, the Undulated Trigger.
Odonus niger, the Red Tooth Trigger Odonus niger, the Red Tooth Trigger. A juvenile in an aquarium. Rhinecanthus rectangulus, Rectangle Trigger.
Sufflamen albicaudatus, the Blue Throat Trigger, the single triggerfish species confined to the Red Sea. Sufflamen bursa, the Boomerang Trigger. Rhinecanthus assasi, one of the "Picasso" Triggers.

The last seven species are offered from time to time collected from Saudi Arabia and/or Sudan. Due to higher costs of holding and transport, triggerfish with Indo-Pacific range that you see at your dealers are much more likely to hail from the Philippines and islands of Indonesia.

So why would or should you be tempted to spend more on the same species from the Red Sea? Three principal reasons; 1) They're more attractive, 2) Tend to be more "mellow" temperament wise, and most importantly 3) Are hardier than the same fish found anywhere else.

Call it "the mystery of the Red Sea", better, more careful collection, holding and shipping techniques, whatever you'd like; most livestock from this area is better.

A few personal comments about the better of the available Red Sea species. The two Pseudobalistes species get big, fast, about two feet; they are on the mean side of the curve. The niger and undulated triggers are bad boyz from other places in the world. In spite of this, the Red Sea ones are far easier-going. The Rhinecanthus here are medium in temperament and deviation of the same. Lastly, the Sufflamen genus, contains the areas least aggressive triggers.


Most species are in the half to a foot range in length, with a few getting to over two feet long. Looking at them sometimes as an unwelcomed diver, I can assure you that some seem a lot bigger than that. Irrespective of size these fishes are tough customers.

Selection: General to Specific

The point regarding individualism needs to be re-emphasized; the majority of Triggerfishes are territorial and by human standards seem outright mean! Be leery of generalizations regarding this group; amongst fishes they demonstrate a high degree of complex and learned behavior, along with an enormous range of individuality, Each specimen is different.

Should you even acquire a trigger? Even small one's can "turn mean" so I am only suggesting that aquarists with some capacity for separating an antagonist (a "spare", hospital, quarantine tank, serious divider) attempt one or more triggers. Because of their indiscriminate "sampling habits", Balistids are for "fish only" systems. I know there are some who would argue with me about the latter issue; and have kept triggers with corals and more, but I caution the initiated against this.

The following criteria are what I'd select for:

1) Friendliness.

 No, you don't need to risk a finger shaking fins. I'm referring to the fish's interest in it's environment. Is it out, swimming, checking out the system and you? Good.

2) Feeding

Yes, the old standby measure. A trigger that doesn't eat is rare, and trouble; let it by.

2) Size;  

Try to get triggers that are smallish, 2 to 3 inches or sol they more adaptable, easier on tankmates and to train on prepared foods. Unfortunately Red Sea imported fishes shy on larger sizes.

3) Damage;  

I wouldn't be concerned about an individual with fins that are slightly torn or that appears thin. Cloudy eyes, open wounds would disqualify a purchase but otherwise triggers are tough and readily repair.

I urge you to take proper precautions when transporting these fishes. First, don't use your best nets, they'll soon be bit through. Better to direct the intended into submersed multiple thickness bags or specimen container/filter box. Use a Styrofoam box, clean cooler or large fish bucket to move the bagged specimen in, due to vigorous biting and spinning.

Environmental: Conditions


You should provide what the triggers are found around in the wild; plenty of rocks, caves, other decor for hiding and play spaces. Take care to stack heavy objects well; your trigger will be doing some re-arranging.


Though triggers are husky, messy feeders they appreciate good water quality. For former Red Sea inhabitants temperature's in the high seventies, a high pH value (8.2-8.4) and higher specific gravities than many people keep for fish-only systems (1.025). Vacuuming your gravel during frequent, partial water changes, ideally once a week is a very good idea.


Triggers aren't as susceptible as most other marine aquarium fish groups to nitrogen "burning". They've actually been used in other countries to establish nutrient cycling. Regardless, your system should have vigorous circulation/macro-filtration; a wet-dry, large outside power or canister filter, not a soon-to-be-uncovered undergravel filter alone.

Behavior: Territoriality

This can be a/the big problem with this group. Do not crowd triggers! And make sure they're adequately fed. Either lacking results in less colorful, sulking or bullying fishes.

Slow, unwitting species are not good mixers with aggressive triggers. Lionfishes and eels, for instance, are often subject to biting trigger taunts.


Don't be surprised that your new specimen hightails it for the darkest, least accessible cranny on introduction. Allow a day or so's respite; you'll soon find your trigger out and about, checking out what there is to see; growing to recognize you and the feeding repertoire.

Predator/Prey Relations

Triggerfishes are occasionally reported as stomach contents items for top predators, but typically, other species are on food-chain receiving end of trigger sampling, particularly non-vertebrates.

Balistid tankmates therefore must be chosen with care. The bigger basses, surgeons, puffers of various sorts have been placed together with good success.


Balistids eat most anything, of food value or no. Cut fish fillet, shrimp, clams, aquarists' hands. Triggerfishes have powerful jaws with formidable dentition; watch your fingers.

I suggest substantial once daily feedings for medium sized triggers, more frequent for small fishes.


The Triggerfishes are susceptible to marine "ich" and "crypt", but respond well to and have wide tolerance of common treatment modes. Livestock from the Red Sea is singled out generally for high and constant specific gravity, but the triggers do not seem to suffer from temporary lowering of specific gravity as "medicine".


The Triggerfishes of the Red Sea are a another blessing from the area. They're more colorful, even more hardy than the already tough triggers from elsewhere, and by my experiences (first and second hand) tend to be more docile than their Indo-Pacific con-specifics.

Nevertheless, the Red Sea Balistids should be approached with caution; they're still as individualistic and prone to nastiness as the other Balistids.

Bibliography/Further Reading:

Anon. The red-toothed trigger fish. Aquarium Digest Intl. #31.

Berry, F.H. & L.E. Vogele. 1966. Triggerfishes (Balistidae) of the E. Pacific. Calif. Acad. Sci. Ser. 4, 34:429-474.

Burgess, Warren E., Axelrod, Herbert R. & Raymond E. Hunziker. 1990. Atlas of Aquarium Fishes Reference Book, v.1 Marine Fishes. T.F.H. Publications, NJ.

Campbell, Douglas G. 1979. Fishes for the beginner; A guide for the new marine hobbyist - part five; Triggerfish. FAMA 3/79.

Chlupaty, Peter 1991. The blue-and-gold triggerfish, Pseudobalistes fuscus. TFH 4/91.

Clothier, C.R. 1939. The trigger mechanism of a triggerfish (Capriscus polylepis). Calif. Fish Game 25:233-236.

Dareste, C. 1872B. On the natural affinities of the Balistidae. Ann. Mag. Nat Hist. Ser. 4, 10:68-70.

Dor, Menahem 1986. Checklist of the Fishes of the Red Sea. Israel Academy of Sciences and Humanities, Jerusalem.

Edmonds, Les 1994. Trigger happy fish. TFH 8/94.

Fenner, Robert. 1997. Rating the triggers of the Red Sea. TFH 10/97.

Fong, Jack. 1992. The ten most aggressive triggers. TFH 12/92.

Fraser-Brunner, A. 1935A. Notes on the plectognath fishes I. A synopsis of the genera of the family Balistidae. Ann. Mag. Nat. Hist. Ser. 10, 15:658-663.

Herre, Albert W.C.T. 1924. Poisonous and worthless fishes. An account of the Philippine plectognaths. Phil. J.Sci. 25, no.2.

Krechmer, Michael 1995. The labyrinth triggerfish, Pseudobalistes fuscus. TFH 5/95.

Michael, Scott W. 1995. Trigger talk. SeaScope, v. 12, Summer 95.

Michael, Scott W. 1995. Bad beauty; a triggerfish that is bad to the bone (B. undulatus). AFM 12/95.

Miklosz, John C. 1972. Trigger Fishes. Marine Aquarist Magazine. 3(2), 1972.

Nelson, J.S. 1976. Fishes of the World. Wiley-Interscience.

Randall, J.E. & J.T. Millington. 1990. Triggerfish bite - a little known marine hazard. J. Wilderness Med. 1(2) 1990: 79-85.

Takai, A. & Y Ojima. 1987. Comparative chromosomal studies in three Balistid fishes. Kromosomo (Tokyo) Nos. 47-48. 1987. 1545-1550, illustr.

Tyler, Jones. 1980. Osteology, phylogeny & higher taxonomy of the Order Plectognathi (Tetraodontiformes). NOAA Tech. Rept. NMFS Circ 434:1-422 /or Acad. Nat. Sci. Philad. Monog. 16, 364pp.

Triggerfishes for  Marine Aquariums
Diversity, Selection & Care

New eBook on Amazon: Available here
New Print Book on Create Space: Available here

by Robert (Bob) Fenner

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