CKSTrigs

/A Diversity of Aquatic Life

Triggerfishes of the Cook Islands

Bob Fenner

Sufflamen bursa

Balistidae, the Triggerfishes. This area is a balistid lovers paradise. All told there are fourteen triggers in the Cooks?

"Nice" ones from here include:

The three "Lagoon Triggers" often sold as "Picassos", Rhinecanthus aculeatus (aka, the Blackbar Trigger), Rhinecanthus lunula (aka the Halfmoon Triggerfish) and Rhinecanthus rectangulus (aka the Wedge-tail Trigger). Other relatively (for the family!) easygoing Triggers from here include the Black Triggerfish found all around the world in tropical seas, Melichthys niger, and the shy Pinktail Trigger, Melichthys vidua. Though it?s not a great beauty, we?ll mention the Lei or Boomerang Trigger, Sufflamen bursa here as it?s found in the Cooks and isn?t so aggressive?

Rhinecanthus abyssus Matsuura & Shiobara 1989, the Deepwater Triggerfish. Western Pacific. To about eight inches in length.

No pic

The most popular Rhinecanthus species is immortalized in the song of none other than Don Ho himself. This is the Humuhumu nukunuku apua’a (literally "water pig with a needle" in Hawaiian, in reference to grunting noise they make and their spiny dorsal "trigger"), AKA the Picasso or Lagoon Trigger (aka the "Blackbar" to science), Rhinecanthus aculeatus (Linnaeus 1758). Two and six inch specimens in captivity shown.

One of the most rare members of the family, the Halfmoon Picasso or Crescent Trigger, Rhinecanthus lunula Randall & Steene 1983, can be had for a few hundred dollars out of Fiji or Australia.

No pic

The Rectangle or Reef Triggerfish ("Wedge-Tail Triggerfish" to science), Rhinecanthus rectangulus (Bloch & Schneider 1801)shares the waters and common Humu name with the Picasso in Hawai’i. Indo-Pacific, Red Sea, east African coast. Shown here in Hawai'i. To one foot in length.

Most wholesalers offer two species of Melichthys more or less continuously, the circumtropical Black (Durgon) Triggerfish, Melichthys niger (Bloch 1786) (usually out of Hawai’i), to eighteen inches. Pictured: an individual in the Bahamas, and one in Maui, Hawai'i.

And the Pinktail Trigger, Melichthys vidua (Richardson 1845), is the other commonly offered member of the genus. Found throughout the Indo-Pacific. These are "medium" aggressive fish species that grow to about a foot in length in captivity, sixteen inches in the wild. Here are specimens in captivity and Hawai'i.

Most commonly offered are the Sickle, Lei or my favorite, Boomerang Triggerfish, Sufflamen bursa (Bloch & Schneider 1801), (mainly out of Hawai’i), an adult there shown and a smaller (four inch) individual in the Cooks.

Bad Boys:

Such can?t be said for the bruisers, the Undulated Trigger, Balistapus undulatus, The Titan Trigger, Balistoides viridescens, Redtoothed Trigger, Odonus niger, Yellow-margin Trigger, Pseudobalistes flavomarginatus and Yellow-spotted Triggerfish, Pseudobalistes fuscus. These are fishes of considerable ultimate size and capacity for doing major damage to peaceful fishes and most invertebrates.

Balistapus undulatus (Park 1797), the Undulated or Orange-Lined Triggerfish is both loved and vilified in our hobby. On the one hand it’s a gorgeous species that is very hardy. On the other it can be a pure terror towards its tank-mates, eating or "sampling" them all to death. Don’t despair if you have a penchant for keeping this fish. True, most Indo-Pacific ones are mean to a fault and must be kept only with like-mad-minded fishes, but do look for the more mellow Red Sea specimens if you can. These are much more peaceful toward other species.

The Titan Trigger, Balistoides viridescens (Bloch & Schneider 1801), tops out at about two feet. Here much more subdued hiding under an Acroporid coral... much better than leaving its nest to come bite you!

The Red-Toothed or Niger Trigger, Odonus niger (Ruppell 1836), gets its first name from the color around the mouth that develops as the fish attains maximum size (to 18 inches). Indo-Pacific, Red Sea. This is generally a medium aggressive species, safe for rough and tumble fish-only systems. An aquarium specimen and one in Moorea, French Polynesia.

Yellow Fin, Margin or Face Triggerfish, Pseudobalistes flavimarginatus (Ruppell 1829). A beauty and peaceful for a triggerfish when small. To two feet. Indo-west Pacific, Red Sea to along Africa's eastern coast to Natal. Here is a one inch individual in the Maldives and an adult in the Andaman Sea off Thailand.

The Blue Line Triggerfish ("Yellow-Spotted Triggerfish" to science), Pseudobalistes fuscus (Bloch & Schneider 1801). Indo-Pacific, Red Sea, east African coast to South Africa. To twenty two inches in length. A juvenile in captivity and a full size adult in the Red Sea shown.

Not mean, but not necessarily hardy.

There are two species of the genus Xanthichthys here as well, but these shy, oceanic species should really only be displayed in huge public aquarium systems. They languish in small (less than thousands of gallons) tanks. Much the same can be said for the circum-tropical Spotted Oceanic Triggerfish found here. It rarely survives long in captivity.

Like the Blue Throat or Gilded Triggerfish, Xanthichthys auromarginatus (Bennett 1832), that are true reef dwellers. Here is a female and a male off of Maui, Hawai'i. Indo-west Pacific. To about a foot total length.

Xanthichthys caeruleolineatus Randall, Matsuura & Zama 1978, the Blue-Line Triggerfish. Indo-west Pacific. To thirteen inches.

No pic

Xanthichthys lineopunctatus (Holland 1854), the Striped Triggerfish. Indo-west Pacific to Africa's east coast. To a foot in length.

No pic.

A more open ocean species, the Redtail or Crosshatch Triggerfish, Xanthichthys mento (Jordan & Gillbert 1882). Entire tropical Pacific. To a foot in length. This one in captivity.

Canthidermis maculatus (Bloch 1786), the Spotted Oceanic Triggerfish. Circumglobal. To twenty inches in length. A pelagic species that adapts poorly to captivity in general. To about a foot and a half in length.

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