Tetraodontiformes

(Pufferfishes, triggerfishes, and relatives)

Class Actinopterygii

Order Tetraodontiformes

Number of families 9

Evolution and systematics

Although it is remarkably derived, this order of fishes dates from the early Eocene epoch or, possibly, the late Cretaceous period. There are nine families, including the spikefishes (Triacanthodidae, 11 genera and 21 species), the triplespines (Triacanthidae, four genera and seven spp.), the boxfishes (Ostraciidae, 11 genera and 37 spp.), the filefishes and leatherjackets (Monacanthidae, 25 genera and at least 104 spp.), the triggerfishes (Balistidae, 12 genera and at least 37 spp.), the threetooth puffer (Triodontidae, one genus and one species), the pufferfishes (Tetraodontidae, 26 genera and at least 170 species, with one species that has two subspecies), the porcupinefishes (Diodontidae, seven genera and 20 spp.), and the molas or ocean sunfishes (Molidae, three genera and four spp.).

Physical characteristics

There is some variability within this order, but all are distinguished by fused teeth within their jaws. Spikefishes are compressed, high bodied (great in depth), or elongate; some have concave foreheads and others elongated, tubelike snouts. The caudal fin is rounded to truncated, and there are 12–18 soft rays in the dorsal fin and 11–16 rays in the anal fin. Coloring is orange, yellow, or pink. Triplespines are compressed and elongate, with steeply sloping foreheads, narrow caudal peduncles, and forked tails. The first dorsal spine is large. The coloring is silvery, with hints of yellow or pale olive. The boxfishes are indeed boxlike, with bodies covered in bony-like plates. They have large rounded or truncated caudal fins and the ability, in numerous species, to secrete ostracitoxin (a poison that makes the creature unpalatable) as an anti-predatation mechanism. Some species have horns that protrude from their heads. A few species are brightly colored, but most are dull or cryptic.

Filefishes and leatherjackets also vary in shape and appearance. Generally, they are compressed and somewhat elongate, and they may have steeply sloped foreheads. Others are rhomboid in shape. At least one species, Anacanthus barbatus, is long and slender and resembles superficially a pipefish (Sygnathidae). The first dorsal spine usually is tall and strong. The caudal fin is truncated or slightly rounded. Color patterns vary, ranging from bright colors to cryptic or nondescript shades. Triggerfishes are compressed, rhomboid, or slightly elongate, with pelvic fins that are fused into a single spine. The first dorsal spine is capable of locking by using the second spine as a trigger that locks it into place. It is used as an anti-predation mechanism. The eyes can rotate independently of each other. Color patterns also vary and may be spectacular and bright or quite dull or cryptic.

The threetooth puffer has a beak consisting of three fused teeth, with a median suture in the upper jaw. The body is

elongate, compressed, and inflatable. The caudal penduncle is long, and the caudal fin forked. Pufferfishes have four teeth fused together to form a beak, but there are medial sutures in both the upper and lower jaws. Their bodies are elongate, usually compressed or rhomboid in shape, and inflatable. There are seven to 18 soft rays in both the dorsal and anal fins, respectively. Many species have small prickles on the skin of their bellies. Their skin, entrails, and sometimes their flesh may contain tetraodotoxin, an anti-predation poison that is highly toxic. Porcupinefishes are large, elongate, robust, and somewhat boxlike, and they are capable of inflation. They have numerous spines along the body. The two teeth on their jaws are fused into a beak. Molas are large, compressed, and typically high-bodied fishes, with jaws that support two fused teeth. The caudal fin may be replaced by a clavus, which is used to stablize the fish when swimming. The dorsal and anal fins are set high. Both the lateral line and swimbladder are missing from adults.

Distribution

Members of this order occur in marine, brackish, and freshwater of the tropics, subtropics, and temperate zones. The spikefishes are tropical and subtropical deepwater residents of the western Atlantic and Indo-Pacific regions. Triplespines occur in shallow marine and brackish waters of the Indo-Pacific region. Boxfishes, triggerfishes, filefishes, and leatherjackets are distributed widely, mainly in coastal waters of the tropical, subtropical, and temperate or warm temperate Atlantic, Indian, and Pacific Oceans. The monotypic threetooth puffer is a deep-slope species of the Indo-Pacific region. Marine pufferfishes occur in tropical and subtropical waters of the Atlantic, Indian, and Pacific Oceans; numerous species enter brackish water or even freshwater. Some strictly freshwater species are found in river systems of Africa, Asia, or South America. Porcupinefishes occur in tropical, subtropical, and warm temperate waters of the Atlantic and Indo-Pacific regions; at least one species is circumglobal in its distribution. Molas also are found in tropical, subtropical, and warm temperate waters of the Atlantic, Indian, and Pacific Oceans but are largely pelagic and venture inshore only occasionally.

Habitat

Habitat preferences and utilization vary widely within this order. Most species are marine, but at least 20 occur in freshwater systems. Spikefishes are bottom dwelling in relatively deep waters. Triplespines also live on the bottom but on shallow marine and brackish water sand flats and mudflats. Boxfishes frequent coral or rocky reefs in relatively shallow water; others occur on sea grass flats and algae beds. Large post-larvae or young juveniles of some species are pelagic and are part of the diet of tunas and billfishes; others enter estuaries. Triggerfishes also are associated with coral or rocky reefs but may be found on rubble and sand flats. Some species are pelagic or semipelagic, the latter dwelling in the water column but seeking shelter in holes on the bottom or along walls. Filefishes and leatherjackets are quite wide ranging in their habitat use. Many species are associated with coral or rocky reefs; others with sponge reefs, sea grass flats, algae beds, or rubble and sand flats; and still others dwell in the water column. The threetooth puffer is a benthic, deep-slope-dwelling fish. Marine and brackish water pufferfishes occur on coral and rocky reefs, on rubble, sand, mud, or sea grass flats; on algae beds; or in the water column. Freshwater species tend to be benthic. Porcupinefishes occur on coral and rocky reefs, usually to seaward, and also utilize caves and holes in relatively shallow water. They also frequent reefs dominated by sponges. The molas are pelagic fishes that prefer the upper depths of the open ocean but also venture inshore, especially near deep-slope habitats that experience upwelling of deeper, cooler water.

Behavior

To some extent, tetraodontiform fishes incorporate their unique body structure and abilities into their patterns of behavior. For defense, feeding, social interaction, or reproduction, they rely variously on body armament; their fused beaks or ability to inflate with water; or their color patterns, which

may advertise toxicity. Adult boxfishes utilize their body armor and ability to secrete ostracitoxin, a compound poisonous to predators (and other fishes, including themselves, if they are kept in a confined space), as defensive mechanisms. Thus, predation risk is minimized as they swim along the bottom or up into the water column. Despite reduction in risk, however, numerous species are quite cryptic as they move about in algae or corals. Boxfishes also are territorial. A majority of triggerfishes are colorful, solitary, and quite aggressive in the defense of their territories. Those species that dwell in the water column often assemble in loose aggregations of up to hundreds of individuals as they forage off walls or along deep slopes. These species quickly retreat to individual shelters when threatened, however.

Filefishes and leatherjackets are solitary or gather in small groups, but some form monogamous pairs that patrol a home range or territory. Others, such as Aluterus monoceros, form large schools. Many species are cryptic as well and take advantage of structure to mask their movements. A few species, such as juvenile Aluterus scriptus, swim on their sides and mimic floating leaves or other vegetation. Some swim openly in the water column, however. The color pattern of some filefishes and leatherjackets may be put to a surprising advantage. For example, the mimic filefish, Paraluteres prionurus, mimics the toxic saddled puffer, Canthigaster valentini, and thus avoids predation. Another species, the diamond filefish (Rudarius excelsius) mimics benthic algae.

Pufferfishes are solitary or paired or form small groups or schools. Many species utilize color pattern to advertise their toxic nature and thus avoid predation. Others are remarkably cryptic and even bury themselves in the sand. Some frequent the water column but return to the bottom for shelter or to feed. All are capable of inflating as a defensive mechanism. When they are not sheltering in holes or caves, porcupinefishes swim openly in the water column and depend on both their large spines and ability to inflate themselves to defend against predation. They reportedly have toxic flesh or organs that may contribute toward their defense as well. Some species have been observed to bury themselves in the sand. Although they are seen swimming during daylight hours, numerous species also are nocturnal. Molas swim about sideways or upright at or near the surface in the open ocean and, despite their ungainly appearance, are relatively strong and fast swimmers when necessary. They also drift on their sides in the current. When they are inshore near kelp beds, they allow themselves to be cleaned by resident cleanerfish species. The behavior of deep-dwelling spikefishes and threetooth puffers is largely unknown. Presumably, these fishes are largely solitary and move about the bottom or in the water column. The threetooth puffer is able to defend itself by inflation.

Feeding ecology and diet

Feeding patterns and dietary preferences of tetraodontiform fishes also vary. Little is known about spikefish feeding. Those species with long, slender, and highly specialized snouts likely pluck microinvertebrates from the bottom or possibly the water column. Species with relatively larger mouths probably feed on benthic invertebrates. At least one species, Macrorhamphosodes uradoi, feeds on the scales of other fishes. Triplespines also eat benthic invertebrates unearthed from sand or mud. Boxfishes are mainly omnivorous and feed upon small invertebrates, especially sessile species, as well as benthic algae. Triggerfishes are more wide ranging in their diet and feed upon benthic invertebrates that include gastropods, bivalves, crustaceans, and various echinoderms. Some species also eat algae, and those that dwell in the water column eat zooplankton. Similarly, filefishes and leatherjackets favor various benthic invertebrates, but some species are specialized to feed upon live corals or zooplankton. The threetooth puffer probably limits its diet to benthic invertebrates. Pufferfishes are remarkable opportunists and feed upon various invertebrates as well as algae. Larger species are

quite capable of breaking open hard-shelled organisms, such as gastropods, bivalves, and crustaceans. Some species are specialized for certain invertebrates, however. Porcupinefishes prefer hard-shelled invertebrates, which they crush with their beaks. The molas utilize their parrot-like beaks to feed upon zooplankton and jellyfishes in the water column but also take fishes, mollusks, crustaceans, and brittlestars when they are inshore or near the bottom in deep-slope areas.

Most members of this order are preyed upon while in the larva or post-larva stage. As adults, relatively few have predators. Successful predators would have to be tolerant of spines, bony plates, and ossicles formed from fused bones, and, in some families, toxins. Some toxic puffers (Tetraodontidae), however, are preyed upon by sea snakes.

Reproductive biology

Depending upon the species, tetraodontiform fishes have diverse mating systems and spawn demersal or pelagic eggs. Seasonality may be pronounced at higher latitudes or in colder, deeper waters. Reproduction also may be linked to lunar or semilunar cycles. Little is known of the reproductive biology of the deep-dwelling spikefishes, threetooth puffers, and shallow-dwelling triplespines, but their eggs are likely demersal and their larvae pelagic. Boxfishes have mainly male-dominated mating groups, court and spawn at dusk, and produce pelagic eggs and larvae. Triggerfishes have varying mating systems, including monogamy, bigamy, and polygyny. They usually spawn demersal eggs in nests that are guarded quite aggressively by females or, to a lesser extent, by males. Larvae are pelagic. The filefishes and leatherjackets studied thus far have mating systems that include monogamy, facultative monogamy, polygyny, female visiting within male territories, or promiscuity. They all appear to lay demersal eggs in nests or on algae. There may be male parental care, female parental care, biparental care. or no care of eggs. The larvae are pelagic and may be adapted for an extended pelagic existence.

Pufferfishes have diverse mating systems and patterns of courtship and spawning. The eggs generally are demersal and are laid in nests on algae or scattered on the bottom. The eggs of some species are poisonous. Porcupinefish reproductive behavior appears to vary within as well as between species. Both pair and group (single female and multiple males) spawning has been reported for Diodon holacanthus. Courtship begins at dusk, and spawning is pelagic in shallow water and may involve splashing at the surface as eggs and milt are released. Alternately, the eggs may sink to the bottom. The larvae are pelagic as well. Eggs of the genus Chilomycterus reportedly are demersal, although their larvae are pelagic. Details of courtship and spawning of molas are not well known. They are highly fecund and produce hundreds of millions of pelagic eggs. The larvae are also pelagic.

Conservation status

A few species are cited on the IUCN Red List. The queen triggerfish, Balistes vetula (Balistidae), the Rapa Island toby, Canthigaster rapaensis (Tetraodontidae), and the blunthead puffer, Liosaccus (= Sphoeroides) pachygaster (Tetraodontidae), are listed as Vulnerable. Five additional species in the family Tetradontidae are listed as Data Deficient. Various species may be at risk from overfishing (as a target species or as bycatch) or habitat destruction. The European Community prohibits the trade of pufferfish products.

Significance to humans

Numerous species of triggerfishes, filefishes and leatherjackets, pufferfishes, and molas are taken in subsistence and artisinal fisheries. Commercial fisheries exist for certain triplespines, triggerfishes, filefishes and leatherjackets, and pufferfishes. The latter group includes the famous fugu (Takifugu spp.), which is esteemed as a delicacy in Japan but poses a serious health risk from tetraodotoxin poisoning if it is not prepared properly. Boxfishes and molas also are or may be poisonous. Various species are used in Chinese medicine. Many species of boxfishes, porcupinefishes, and puffers are taken for use as decorations in the ornamental trade; for example, diodontids are often used to make lamp shades. Some triggerfishes and filefishes and leatherjackets are considered game fishes. Many species of triggerfishes, filefishes and leatherjackets, and pufferfishes (both marine and freshwater) are collected for the aquarium trade, and some are highly valued.

Species accounts

List of Species

Orange-striped triggerfish

Balistapus undulatus

family

Balistidae

taxonomy

Balistapus undulatus Park, 1797, Sumatra, Indonesia.

other common names

English: Orange-lined triggerfish; French: Baliste strié; German: Orangestreifen-Drückerfisch; Afrikaans: Oranje streepsnellervis; Japanese: Kumadori.

physical characteristics

Body compressed and oblong, the forehead sloping to above the eye, the caudal peduncle compressed, with a truncate caudal fin. There are three spines, 24–27 soft rays in the dorsal fin, and 20–24 soft rays in the anal fin. The first dorsal spine can be locked. Body color variably green to dark green or dark brown. There is a pattern of orange lines that curve obliquely on the posterior portion of the head and along the body. A band of orange and blue stripes runs obliquely from the mouth to below the pectoral fin. There is a large black blotch on the caudal peduncle. The caudal fin and soft fin rays of the dorsal, anal, and pectoral fins are orange. Grows to at least 11.8 in (30 cm) in total length.

distribution

Tropical and subtropical Indo-West Pacific from the Red Sea and East Africa south to Natal in South Africa, east through Micronesia and the Line Islands to the Marquesas and the Tuamotu Archipelago in eastern Polynesia, south to the Great Barrier Reef of Australia and New Caledonia, and north to southern Japan. New research suggests that populations in the western Indian Ocean, the Indo-Malayan region, and the Pacific may constitute three distinct species.

habitat

Somewhat ubiquitous on reefs; may be found on seaward or protected reefs and in lagoons at depths ranging from about 6.6 to 164 ft (2–50 m).

behavior

Territorial and generally solitary, although individuals may live in somewhat close proximity to one another and have overlapping home ranges.

feeding ecology and diet

Omnivorous. Feeds on sponges, hydrozoans, tunicates, mollusks, echinoderms, small fishes, and algae.

reproductive biology

Pair-spawns, with a single cluster of eggs deposited in a shallow nest excavated in rubble or sand. Larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

A minor commercial or subsistence food fish in some areas that is either dried and salted or sold fresh. Also collected for the aquarium trade.

Clown triggerfish

Balistoides conspicillum

family

Balistidae

taxonomy

Balistoides conspicillum Bloch and Schneider, 1801, Indian and American seas.

other common names

French: Baliste lépreaux; German: Leoparden-Drückerfisch; Afrikaans: Nas-snellervis; Japanese: Mongarakawahagi.

physical characteristics

Body and caudal peduncle are compressed; the body is robust and oval in shape. There are three spines and 25–27 soft rays in the dorsal fin as well as the anal fin. The first dorsal spine can be locked into an erect position. The caudal fin is somewhat rhomboid in shape. The body's color pattern is unmistakable. The background color is black, with large white spots along the flank, a white breast and band below the eye, a white caudal peduncle, and an alternating pattern of black, white, and black on the caudal fin. The mouth is yellow or orangish yellow, with a thin yellow stripe on a black background. Faint yellow hues are found along the base of the anal fin and on the caudal peduncle. The dorsal, lower anal, pectoral, and pelvic fins are white. Grows to at least 19.7 in (50 cm) in total length.

distribution

Tropical and subtropical Indo-West Pacific from East Africa and South Africa east to Samoa, south to northern Australia and New Caledonia, and north to southern Japan.

habitat

Occurs mainly on seaward reefs or passes along or adjacent to deep slopes or walls, from just below the surge zone to at least 246 ft (75 m).

behavior

Generally solitary, territorial, and even aggressive.

feeding ecology and diet

Feeds upon benthic invertebrates, mainly crustaceans, including crabs, as well as sea urchins, mollusks, and tunicates.

reproductive biology

Reproduction is consistent with that of others in the family, but greater detail is needed. Pair-spawns. Lays and defends demersal eggs in a nest. The larvae are pelagic.

conservation status

Not listed by the IUCN but relatively rare in many localities and may be vulnerable to overfishing.

significance to humans

A highly prized aquarium fish species, often collected as juveniles or subadults but occasionally full grown for larger aquaria. Also taken in subsistence and minor commercial food fisheries but has been implicated in ciguatera poisoning in humans.

Blackbar triggerfish

Rhinecanthus aculeatus

family

Balistidae

taxonomy

Rhinecanthus aculeatus Linnaeus, 1758, India.

other common names

English: Picassofish; English and Hawaiian: Humu humu; French: Poisson picasso sombre; German: Gemeiner Picassodrücker.

physical characteristics

Body compressed and somewhat oblong or rhomboid. The forehead slopes upward past the eye to just anterior to the dorsal fin. There are three spines and 23–26 soft rays in the dorsal fin and 21–23 soft rays in the anal fin. The color pattern is gray to grayish brown on the head and just below the dorsal fin and brown to brownish gray along the upper flank, with two thick and two thin oblique stripes of the same color extending down, in alternation, onto the lower flank and belly. An orangish brown bar extends from midflank up and back to the base of the soft rays of the dorsal fin. The lower flank and belly are white. A thin yellowish line runs from the mouth back to just past the lower part of the operculum. There is a black to brown blotch extending from the posterior portion of the flank onto the white caudal peduncle and a black blotch around the anus. The fins are pale to light gray. Reaches 11.8 in (30 cm) in total length.

distribution

Tropical and subtropical Indo-West Pacific from the Red Sea and East Africa; south to South Africa; east to the Tuamotu Archipelago, Marquesas, and Hawaiian Islands in Polynesia; south to northern Australia and Lord Howe Island; and north to southern Japan. Also reported from the eastern Atlantic from Senegal south to South Africa.

habitat

Coral and rocky reefs, mainly on reef flats or in shallow lagoons on rubble and sand. Depth range is 3.3–13 ft (1–4 m).

behavior

Highly territorial, especially when guarding a nest. Excavates or utilizes a small hole for shelter, where it can lock itself in by extending its first dorsal spine. It sleeps on its side there. Patrols a territory and may inflict a painful bite upon intruders or passersby. Produces a whirring sound when alarmed.

feeding ecology and diet

Omnivorous. Feeds upon mollusks, crustaceans, worms, sea urchins, corals, small fishes, tunicates, foramniferans, fish eggs, algae, and detritus.

reproductive biology

The mating system is single male/multiple female polygyny, but facultative monogamy occurs occasionally. Spawning takes place on a semilunar cycle. Spawning is paired, and eggs are deposited on the substratum within a territory. The eggs are demersal and guarded. The larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

An important fish in the aquarium trade but also taken as food in minor commercial and subsistence fisheries.

Spot-fin porcupinefish

Diodon hystrix

family

Diodontidae

taxonomy

Diodon hystrix Linnaeus, 1758, India.

other common names

English: Spot-fin porcupinefish; French: Diodon porc-épic; German: Gepunkter Igelfisch; Afrikaans: Penvis; Japanese: Nezumifugu.

physical characteristics

Body elongate, stocky, and inflatable. Several long, strong spines cover the body, with a row of 20 stretching from the snout to the dorsal fin. The jaw has two fused teeth that are quite adept at crushing food items. There are 14–17 soft rays in the dorsal fin and 14–16 soft rays in the anal fin. The body color is grayish-tan, with small black spots and a white belly. A dusky-colored ring surrounds the belly. Grows to more than 35.4 in (90 cm) in total length.

distribution

Essentially circumglobal in tropical, subtropical, and warm temperate waters. From East Africa to San Diego, California, and Chile and the Galapagos Islands. Also in the Atlantic from Massachusetts and Bermuda to Brazil and from the Iberian Peninsula south to southern Africa.

habitat

Frequents coral and rocky reefs, usually in caves and holes to a depth of 164 ft (50 m). Swims in the water column during low-light periods.

behavior

Generally solitary. Reportedly nocturnal but occasionally active in daylight.

feeding ecology and diet

Prefers hard-shelled benthic invertebrates that include gastropods, hermit crabs, and sea urchins.

reproductive biology

Not well known, but paired courtship involving chasing has been observed just before sunset. Probably spawns demersal eggs. The larvae are pelagic.

conservation status

Not listed by the IUCN. May be vulnerable to overfishing, because it is normally not common anywhere.

significance to humans

Poisonous and not taken for food but collected and dried for use as ornaments.

Mola

Mola mola

family

Molidae

taxonomy

Mola mola Linnaeus, 1758, Mediterranean Sea.

other common names

English: Ocean sunfish.

physical characteristics

Body large, tall, and compressed. The body is scaleless, with a thick, elastic skin. The mouth is small, with a parrot-like beak formed by fused teeth. The caudal fin is replaced by a clavus, a rudder-like body-fin adaptation. Both the dorsal and anal fins have relatively short bases but are very high. These fins are flapped in a synchronous motion that allows for reasonably good speed and also for swimming sideways. The pectoral fins are small and point upward toward the dorsal fin. There are 15–18 soft rays in the dorsal fin and 14–17 soft rays in the anal fin. The swim bladder is absent in adults. The color is silvery gray. The tips of the dorsal and anal fins and the clavus are darkly colored. Grows to more than 130 in (330 cm) in total length. Flesh may be toxic.

distribution

Circumglobal in tropical, subtropical, and warm temperate waters.

habitat

Frequents the pelagic realm but will move inshore to kelp beds. May be carried inshore by upwelling to the deep slopes of coral or rocky reefs. Depth range from surface down to 985 ft (300 m).

behavior

Solitary but occasionally found in small groups. Swims up to the surface and even exposes its dorsal fin in the air. Also lies on its side.

feeding ecology and diet

Feeds on jellyfishes, larger zooplankton, crustaceans, and fishes; also takes mollusks and brittle stars inshore.

reproductive biology

Not well known, but courtship probably is paired. Adult females are very fecund. Larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

Prized as a delicacy in some places but avoided as poisonous elsewhere. Used in Chinese medicine. May be collected incidentally for large aquaria, but this species does not do well in captivity.

Scrawled filefish

Aluterus scriptus

family

Monacanthidae

taxonomy

Aluterus scriptus Osbeck, 1765, China Sea.

other common names

French: Robe de cuir; German: Schrift-Feilenfisch; Afrikaans: Bekrapte leerbaadjie; Japanese: Sôshihagi.

physical characteristics

Body compressed, elongate, and somewhat rhomboid, with a concave snout and a relatively large and rounded caudal fin. There are two spines and 43–50 soft rays in the dorsal fin and 46–52 soft rays in the anal fin. The color is olive-brown to gray or tan with blue lines and spots in adults and yellowish brown with black spots in juveniles. Grows to more than 43.3 in (110 cm) in total length.

distribution

Tropical, subtropical, and warm temperate waters worldwide. In the Indo-Pacific from South Africa east to the Gulf of California and Colombia. In the Atlantic from Nova Scotia south to Brazil in the west and at Saint Paul's Rocks, Cape Verde, Ascension Island, and São Tomé Island in the east.

habitat

Found on seaward or lagoon coral reefs, rocky reefs, sea grass beds, and algae beds. Occasionally shelters under floating trees or other objects. Depth range is 13–394 ft (4–120 m).

behavior

A solitary species that, despite its relatively large size, often moves cryptically within or between habitats.

feeding ecology and diet

Omnivorous. Feeds on hydrozoans, gorgonians, colonial anemones, tunicates, sea grass, or algae.

reproductive biology

Not well known but probably lays demersal eggs. The larvae are pelagic and well equipped for a long pelagic existence, thus explaining this species' remarkable pattern of geographical distribution.

conservation status

Not listed by the IUCN.

significance to humans

Collected for the aquarium trade. Also a game fish at some localities. Taken for subsistence elsewhere. This species has been reported to cause ciguatera poisoning.

Longnose filefish

Oxymonacanthus longirostris

family

Monacanthidae

taxonomy

Oxymonacanthus longirostris Bloch and Schneider, 1801, East Indies.

other common names

English: Harlequin filefish; French: Baliste à taches orange; German: Palettenstachier; Japanese: Tengukawahagi.

physical characteristics

Body compressed and elongate with a pronounced, almost tubular snout. There are two spines and 31–35 soft rays in the dorsal fin and 29–32 soft rays in the anal fin. The color is bright green with orange spots or elongated blotches. The eyes are ringed with orange. The caudal fin is whitish with a small dark spot posteriorly. Grows to 4.7 in (12 cm) in total length.

distribution

Tropical and subtropical Indo-West Pacific from East Africa and Mozambique east to Samoa and Tonga, north to southern Japan, and south to the southern Great Barrier Reef and New Caledonia. The very similar congener O. halli replaces it in the Red Sea.

habitat

Found on coral-rich seaward and lagoon reefs, including reef flats, between 1.6 and 98 ft (0.5–30 m).

behavior

Males and females most often are found in pairs that jointly patrol a shared territory. Territoriality is especially pronounced during mating season, and territorial defense is greater among males than females during this time, because females generally spend more time feeding. Aggressive behavior takes place in relation to food or mates. Males are capable of defending territories successfully alone during mating season, but females are not.

feeding ecology and diet

Feeds upon Acropora spp. coral polyps.

reproductive biology

This species usually is monogamous but is facultatively polygynous in relation to the availability of mates locally. If males are in short supply, a male may have a two-female mating group. Eggs are demersal and laid almost daily during the season on a piece of filamentous algae, but no care is given. Algae that is toxic is preferred, because of the anti-predation advantage that it confers, in the absence of parental care, upon the eggs. The larvae are pelagic.

conservation status

Not listed by the IUCN but may be vulnerable because of coral bleaching.

significance to humans

Collected for the aquarium trade but does not do well without live coral.

Longhorn cowfish

Lactoria cornuta

family

Ostraciidae

taxonomy

Lactoria cornuta Linnaeus, 1758, India.

other common names

French: Coffre cornu; German: Langhorn-Kofferfisch; Afrikaans: Langhoring-koeivis; Japanese: Kôngo-fugu.

physical characteristics

Boxlike body, with two long "horns" projecting forward from the top of the head just in front of the eyes. The mouth is subterminal with prominent lips. The dorsal fin is relatively small and arises just forward of the caudal peduncle. The caudal fin is rounded. There are eight or nine soft rays in the dorsal fin, eight to nine soft rays in the anal fin, and nine to 10 rays in the caudal fin. Body color ranges from green and olive to light orange with blue spots and is cryptic. Grows to at least 18.1 in (46 cm) in total length.

distribution

Indo-Pacific in tropical, subtropical, and warm temperate waters from East Africa and the Red Sea east to the Tuamotu Archipelago and the Marquesas in eastern Polynesia, north to southern Japan and southern Korea, and south to Australia and Lord Howe Island.

habitat

Coral and rocky reefs, especially in algae beds or sea grasses. Juveniles enter brackish waters of estuaries. Depth range is 3.3–328 ft (1–100 m).

behavior

Adults usually are solitary and territorial, but the juveniles form small groups.

feeding ecology and diet

Forages for benthic vertebrates by blowing water into the sand to dislodge them.

reproductive biology

The mating system consists of a single male with a small group of females within its territory. Practices elaborate courtship just before or after sunset. Courtship is paired and results in the release of pelagic eggs well up into the water column above the bottom. The larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

An interesting aquarium species but one that should be kept alone or with species with which it is not likely to interact. Also taken as a minor subsistence species that may cause ciguatera poisoning. Most are probably dried and sold as ornaments.

Yellow boxfish

Ostracion cubicus

family

Ostraciidae

taxonomy

Ostracion cubicus Linnaeus, 1758, India.

other common names

French: Poisson cube; German: Gelbbrauner Kofferfisch; Afrikaans: Koffertije; Japanese: Minami-hakofugu.

physical characteristics

Boxlike body with bony plates, a steeply sloping forehead, a subterminal mouth, a thick caudal peduncle, and a relatively large, somewhat rounded caudal fin. The dorsal and anal fins are positioned well back, just forward of the caudal peduncle. Body color of adults is a dirty yellow with a blueish hue and yellow seams between the body's bony plates. Juveniles are an attractive bright yellow with small black spots. There are eight or nine soft rays in the dorsal fin, nine soft rays in the anal fin, and 10 caudal fin rays. Total length up to 11 in (28 cm).

distribution

Tropical and subtropical waters of the Indo-Pacific and southeastern Atlantic, from East Africa and the Red Sea east to the Hawaiian Islands and the Tuamotu Archipelago in Polynesia, north to the Ryukyu Islands of southern Japan, south to Australia and Lord Howe Island, and off southern Africa in the Atlantic.

habitat

Primarily coral reefs in lagoons, on reef flats, and on protected seaward reefs. Juveniles associate with Acropora corals. Depth range is 3.3–148 ft (1–45 m).

behavior

Adults are solitary and territorial. Juveniles also are solitary after settlement. Secretes ostracitoxin as a defensive mechanism when attacked or disturbed.

feeding ecology and diet

Omnivorous. Feeds upon benthic algae, various microorganisms, and foraminiferans that it strains from sediments, sponges, polychaete worms from sand flats, mollusks, small crustaceans, and small fishes. Large larvae and post-larvae often taken by pelagic predators, such as tunas.

reproductive biology

Paired courtship just before or after sunset. Eggs and larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

Collected for the aquarium trade but, due to its ability to secrete ostracitoxin, usually is a poor choice for a community aquarium.

White-spotted puffer

Arothron hispidus

family

Tetraodontidae

taxonomy

Arothron hispidus Linnaeus, 1758, India.

other common names

French: Tetrodon marbré; German: Weissflecken-Kugelfisch; Afrikaans: Witspikkel-blaasop; Japanese: Sazanamifugu.

physical characteristics

Body elongate, robust, and capable of inflation with water. There are small spines on the body, except for the snout and caudal peduncle. The jaw teeth are fused but separated by a median suture. There are 10–11 soft rays in both the dorsal and anal fins. The caudal fin is rounded. Two fleshy tentacles emerge from each nostril. The gill opening is restricted, and the single lateral line is bent. The color is greenish brown with small white spots on the back, flanks, and caudal fin. The belly has white bars. Grows to at least 19.7 in (50 cm) in total length.

distribution

Tropical and subtropical waters of the Indo-Pacific from the Red Sea and East Africa to Panama and the Gulf of California; also north to Japan and throughout Micronesia and Polynesia as far as the Hawaiian Islands and Rapa Island and south to Australia and Lord Howe Island.

habitat

Coral and rocky reef slopes, lagoons, and inner reef flats over sand, rubble, or patch reefs. Juveniles found among weeds in estuaries or on reef flats. Depth range is 3.3–164 ft (1–50 m).

behavior

Solitary and territorial. Individuals may bury themselves partially in the sand.

feeding ecology and diet

Omnivorous, feeding on fleshy coralline or calcareous algae, detritus, sponges, corals, anenomes, tube worms, mollusks, crabs, echinoderms, and tunicates.

reproductive biology

Not well known. Probably lays demersal eggs. Larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

Collected for the aquarium trade.

Spotted toby

Canthigaster solandri

family

Tetraodontidae

taxonomy

Canthigaster solandri Richardson, 1845, Polynesia.

other common names

English: Spotted sharpnose puffer.

physical characteristics

Oblong and stocky body, with a pronounced snout, prickles on the belly, a rounded caudal fin, and the ability to inflate itself with water. Color is orangish red with blue spots over much of the body and on the orange caudal fin. The ventral surface is white. There is a black spot ringed in pale blue directly below the base of the dorsal fin. The dorsal fin is white, with a black base, and has eight to 10 soft rays. The anal fin also has eight to 10 soft rays. Some geographical variation in color pattern. The skin contains tetraotoxin. Grows to at least 4.3 in (11 cm) in total length.

distribution

Tropical and subtropical waters of the Indo-West Pacific from East Africa east to the Tuamotu Archipelago, south to the Great Barrier Reef and New Caledonia, and north to the Ryukyu Islands of southern Japan. Reportedly strays to the Hawaiian Islands.

habitat

Mainly coral reefs on reef flats, lagoon patch reefs, and seaward reefs. Depth range is 3.3–118 ft (1–36 m).

behavior

Usually paired but also solitary or in groups. Swims over a home range, inspecting potential food items; also swims up in the water column. Some territorial interactions, as well.

feeding ecology and diet

Omnivorous, feeding on tunicates, bryozoans, echinoderms, crustaceans, mollusks, polychaete worms, corals, coralline red algae, green algae, and red algae.

reproductive biology

Paired spawning of demersal eggs on algae growing on dead coral, rocks, or other substrata. The eggs are poisonous, and parental care is not practiced. The larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

Collected for the aquarium trade.

Fugu

Takifugu rubripes

family

Tetraodontidae

taxonomy

Takifugu rubripes Temminck and Schlegel, 1850, "Coasts of Japan."

other common names

Japanese: Torafugu (tiger fugu).

physical characteristics

Body oblong, compressed, and covered with prickles. Color is dark gray or grayish olive dorsally and white ventrally. A large black spot, ringed in white, is positioned on the flank just behind the pectoral fin. The dorsal fin has 16–19 soft rays, and the anal fin has 13–16 soft rays. The caudal fin is truncate. Poisonous, especially the ovaries, liver, and intestines. Grows to 27.6 in (70 cm) in total length.

distribution

Temperate waters of the northwest Pacific from the East China Sea and the Yellow Sea to the Sea of Japan as far north as Hokkaido.

habitat

Rocky reefs and shingle flats, usually up in the water column. Also frequents inlets and brackish waters but moves offshore with age and growth. Depth range is 3.3–656 ft (1–200 m).

behavior

Solitary or in loose groups. This species swims about in the water column.

feeding ecology and diet

Omnivorous, feeding mainly on invertebrates.

reproductive biology

The breeding season runs typically from March to May. Spawning is paired. Eggs are demersal and attached to rocks at depths of less than 65.6 in (20 m). Larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

Highly prized in commercial fisheries of Japan. May be taken incidentally for aquaria. Also used in Chinese medicine.

Spikefish

Halimochirugus alcocki

family

Triacanthodidae

taxonomy

Halimochirugus alcocki Weber, 1913, Arafura Sea.

other common names

Japanese: Nagakawamuki.

physical characteristics

Elongate body; the snout is tubular and elongate. There are six spines and 12–13 soft rays in the dorsal fin; the third spine is minute and protrudes through the skin, whereas the remaining spines lie beneath the skin. The anal fin has 11–12 soft rays. Grows to 6.7 in (17 cm) in total length.

distribution

Western Pacific from central Japan south to the Philippines and Indonesia.

habitat

A bottom-dwelling tropical and subtropical marine species at depths of 1,280–2,001 ft (390–610 m).

behavior

Not well known.

feeding ecology and diet

Not well known but probably feeds on small benthic invertebrates that it takes with its tubelike snout.

reproductive biology

Not well known but likely has demersal eggs and pelagic larvae.

conservation status

Not listed by the IUCN.

significance to humans

Not significant as a food, sport, or aquarium species; of scientific interest, warranting further investigation.

Triplespine

Triacanthus biaculeatus

family

Triacanthidae

taxonomy

Triacanthus biaculeatus Bloch, 1786, East Indies.

other common names

English: Short-nosed tripodfish; Japanese: Gima.

physical characteristics

Body oblong and compressed, with a long caudal peduncle, a deeply forked caudal fin with rounded lobes, a pronounced snout in the head, and a prominent dorsal spine. The dorsal fin has 20–26 soft rays, and the anal fin has 13–22 soft rays. Body color is silvery with a yellowish hue. The caudal fin is pale yellow and somewhat clear at the lobes. The fins are pale or milky to clear white, except for the dorsal spine, which is black at the base. Grows to at least 11.8 in (30 cm) in total length.

distribution

Indo-West Pacific region from the Persian Gulf east across the Indian Ocean to the east coast of Australia and north to China and southern Japan.

habitat

A shallow-water bottom-dwelling species in tropical and subtropical waters. Prefers sand or mudflats of estuaries and inshore coastal waters. Depth range to 197 ft (60 m).

behavior

Not well known.

feeding ecology and diet

This species forages for benthic invertebrates.

reproductive biology

Not well known but probably has demersal eggs, perhaps in a nest, with parental care. The larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

A minor commercial and subsistence species that also is used in Chinese medicine.

Threetooth puffer

Triodon macropterus

family

Triodontidae

taxonomy

Triodon macropterus Lesson, 1831, Mauritius, Indian Ocean.

other common names

Afrikaans: Drietand-blaasop; Japanese: Uchiwafugu.

physical characteristics

Body oblong and compressed, with a well-developed ventral flap. The teeth are quite large and arranged in a beaklike plate; the lower teeth are completely fused, and the upper teeth are separated by a suture. Color is golden yellow with hints of white. There is an irregular black blotch, ringed in white, located medially at the base of the ventral flap. The dorsal and anal fins are relatively small and positioned posterior to the ventral flap. The dorsal fin has two spines and 10–12 soft rays, and the anal fin has nine to 10 soft rays. The caudal fin is slightly forked. Grows to 15.7 in (40 cm) in total length.

distribution

Tropical and subtropical waters of the Indo-Pacific from East Africa to Indonesia and the Philippines north to Japan and south to Australia and New Caledonia.

habitat

A deep-slope demersal species found above the bottom at depths of 164–984 ft (50–300 m).

behavior

Not well known. Can inflate its body with water when threatened or attacked.

feeding ecology and diet

Not well known but probably feeds on benthic invertebrates.

reproductive biology

Not well known. Probably lays demersal eggs. The larvae are pelagic.

conservation status

Not listed by the IUCN.

significance to humans

No commercial importance. May be taken incidentally for larger aquaria.

Resources

Books

Eschmeyer, William N., ed. Catalog of Fishes, 3 vols. San Francisco: California Academy of Sciences, 1998.

Helfman, G. S., B. B. Collette, and D. E. Facey. The Diversity of Fishes. Malden, MA: Blackwell Science, 1997.

Leis, J. M., and B. M. Carson-Ewart, eds. The Larvae of Indo-Pacific Coastal Fishes: An Identification Guide to Marine Fish Larvae. Boston: Brill, 2000.

Masuda, H., K. Amaoka, C. Araga, T. Uyeno, and T. Yoshino, eds. The Fishes of the Japanese Archipelago. Tokyo: Tokai University Press, 1984.

Myers, R. F. Micronesian Reef Fishes. 3rd edition. Barrigada, Guam: Coral Graphics, 1999.

Nelson, J. S. Fishes of the World. 3rd edition. New York: John Wiley and Sons, 1994.

Randall, John E., Gerald R. Allen, and Roger C. Steene. Fishes of the Great Barrier Reef and Coral Sea. Honolulu: University of Hawaii Press, 1996.

Smith, M. M., and P. C. Heemstra, eds. Smiths' Sea Fishes. Berlin: Springer-Verlag, 1986.

Thresher, R. E. Reproduction in Reef Fishes. Neptune City, NJ: T.F.H. Publications, 1984.

Periodicals

Ishihara, M., and T. Kuwamura. "Bigamy or Monogamy with Maternal Egg Care in the Triggerfish, Sufflamen chrysopterus." Ichthyological Research 43 (1996): 307–313.

Kawase, H., and A. Nakazono. "Two Alternative Female Tactics in the Polygynous Mating System of the Threadsail Filefish, Stephanolepis cirrhifer (Monacanthidae)." Ichthyological Research 43, no. 3 (1996): 315–323.

Kokita, T., and A. Nakazono. "Pair Territoriality in the Longnose Filefish, Oxymonacanthus longirostris." Ichthyological Research 46 (1999): 297–302.

——. "Spawning Substrate Selection by Female Longnose Filefish, Oxymonacanthus longirostris." Ichthyological Research 46, no. 4 (1999): 429–432.

Nakae, M., and K. Sasaki. "A Scale-Eating Triacanthodid, Macrorhamphosodes uradoi: Prey Fishes and Mouth 'Handedness' (Tetradontiformes, Triacanthoidei)." Ichthyological Research 49, no. 1 (2002): 7–14.

Organizations

IUCN/SSC Coral Reef Fishes Specialist Group. International Marinelife Alliance-University of Guam Marine Laboratory, UOG Station, Mangilao, Guam 96913 USA. Phone: (671) 735-2187. Fax: (671) 734-6767. E-mail: [email protected] Web site: <http://www.iucn.org/themes/ssc/sgs/sgs.htm>

Terry J. Donaldson, PhD