Banded Archerfish

The banded archerfish is a silvery fish of the Indo-Pacific, found mostly in river mouths and mangrove estuaries and moving between fresh, brackish and salt water over its life. It is best known for shooting a jet of water at prey above the surface. It forms a tube by raising its tongue against the roof of its mouth and closes its gill covers quickly to pressurize the water. Most can spit about 150 cm, and larger fish reach 2 to 3 m. It also jumps from the water to seize prey on low overhanging branches. Adults average about 20 cm long and often show four to six dark bars.

About the banded archerfish

The banded archerfish is a silvery, black-barred fish of Indo-Pacific mangrove estuaries, famous for spitting jets of water to knock insects off leaves and into the water. It belongs to the archerfish genus Toxotes and lives in brackish coastal waters from India to the Philippines and northern Australia.

Toxotes jaculatrix was first described in 1767. Both names point to its hunting style. Toxotes is Greek for "archer," a reference to Sagittarius, and jaculatrix means "she who throws," as in a dart or arrow. The fish has also been filed under other scientific names over the years, and its species name is sometimes misspelled jaculator.

The body is oblong and deepest toward the rear, with a pointed snout and a head slightly shorter than the rest of the body. Most banded archerfish average about 20 cm (8 in) long, though they can reach 30 cm (12 in). The body is usually silvery-white, but some fish are yellowish. The back is olive-green or brown, and some individuals have irregular yellow patches between their bars.

The bold markings give the species its name. Four to six broad black bars run down from the back: one in front of the gill cover, one behind it, one below the start of the dorsal fin, one below the soft dorsal fin and sometimes one near the tail. The bars get shorter as the fish ages.

The fins help with identification. The yellowish-green dorsal fin sits far back on the body and has four spines. The anal fin is silver, and the tail fin is a dull green. The eyes are large and, unlike in many fish, positioned for binocular vision.

Behavior and diet

The banded archerfish is an omnivore and is diurnal in its feeding. During the day it comes up to the surface to feed on floating material, including plant matter and insects. It spends nearly all its time at or near the surface, which suits its way of hunting. It also eats crustaceans and small fish underwater, and it sometimes leaps out of the water to grab insects from low branches.

Its signature skill is shooting. The fish raises its tongue against the roof of its mouth to form a tube, then snaps its gill covers shut. That squeezes water through the tube in a fast, narrow jet. Most archerfish can hit targets about 1.5 m (5 ft) away, and larger fish may reach 2 to 3 m (6.5–10 ft). The shot knocks insects off leaves or out of the air and into the water.

Speed matters once the prey falls. The archerfish starts moving toward the landing spot within 100 milliseconds of the shot and can reach it within 50 milliseconds of the insect hitting the water.

Accuracy is remarkable. Light bends where water meets air, which should throw off the aim. Scientists once thought the fish avoided this problem by shooting from directly underneath its target, but later studies showed it hits accurately even at an angle, suggesting it somehow corrects for the bending of light.

Shooting is also a learned skill. Young archerfish form small schools while they learn to aim, which raises the odds that at least one shot will land. In one study, banded archerfish learned to hit moving targets more than 50% of the time, and fish shot more accurately after watching others in their school do it.

Other archerfish affect how they hunt. When members of the same species are watching, a banded archerfish takes longer to shoot, aims more often, and fires from closer range. Researchers think this reduces the chance that another fish will steal its catch.

Banded archerfish usually live in schools and are generally peaceful in a group. Kept alone, they can turn aggressive toward other fish, and larger individuals may bully or even try to eat smaller ones.

Little is known about breeding. Banded archerfish start breeding at about 10 cm (4 in) long and reproduce by spawning. Archerfish release 20,000 to 150,000 eggs at a time. Reports that they travel to saltwater reefs to spawn have not been confirmed, and the species rarely breeds in captivity.

Range and habitat

The banded archerfish lives across the Indo-Pacific. Its range runs from India east through Southeast Asia to the Philippines, south through the Indonesian Archipelago and New Guinea to northern Australia, and out to the Solomon Islands and Vanuatu. It is less common along Australia's southern coast.

Mangrove estuaries are its main habitat, and it is found almost entirely in brackish water. It also turns up in river mouths and prawn ponds, sometimes moves upstream into freshwater rivers, and is associated with reefs. It is often found near overhanging plants, which hold the insects it hunts.

The fish can handle a wide range of salt levels, from fresh to salt water, and moves between them during its life, though not to breed. It favors warm water of about 25 to 30°C (77–86°F).

Banded archerfish vs other archerfish

The banded archerfish is sometimes grouped and sold with the largescale archerfish under the general label "archerfish." A few features separate it from its closest lookalikes.

Conservation status

The banded archerfish is listed as Least Concern on the IUCN Red List, assessed in 2012. It is fairly common in the Indo-Pacific and is not considered endangered.

It plays a minor role in fisheries, where it is sold fresh in markets, and it is collected for the aquarium trade. The main risks are the destruction of mangrove swamps and pollution, which may cause some local declines.