Banded archerfish

The banded archerfish and its relative the largescale archerfish (Toxotes chatareus) are sometimes grouped and sold together under the label "archerfish".[12] However, the banded archerfish has four dorsal spines whereas largescale archerfish has five. The banded archerfish usually has four to five wedge-shaped bands, but largescale archerfish has six or seven spots and shorter bands in a regular, alternating pattern.[12] Unlike the silvery banded archerfish, the largescale is sooty in colour. The banded archerfish may also be confused with the smallscale archerfish, Toxotes microlepis. These are more difficult to distinguish, but the most striking difference is in the last two bands. While both species have four or five wedge-shaped bands, those of the banded archerfish extend to the dorsal fin, whereas those of the smallscale archerfish do not; there are two spots on the dorsal fin separate from the main bar.[12]

Banded archerfish are omnivorous. In the daytime, they come to the surface to feed on floating matter. Their diet comprises plant matter and insects, which they are able to "shoot down".[2] Banded archerfish are also able to capture prey by jumping out of the water and seizing it from low overhanging branches. Young archerfish form small schools while learning aim, increasing the chance that at least one shot will hit the target. Their diet also comprises underwater prey, including crustaceans and small fishes.[13]

The banded archerfish shooting water at insects.

Banded archerfish have mouths adapted to spit jets of water over distance, usually to knock prey into the water. The banded archerfish shoots the jet of water by raising its tongue against the roof of its mouth, forming a tube. The opercula then close quickly, pressurizing water along the tube.[4] Most archerfish are able to spit at a range of 150 centimetres (59 in),[2] though some larger specimens may be capable of ranges of up to 2 to 3 metres (6 ft 7 in to 9 ft 10 in).[4] When a prey is shot down, the banded archerfish begins to move towards the place where it will land within 100 milliseconds and can reach it within 50 ms of its hitting the water.[5]

A study found that banded archerfish could be trained to hit moving targets at an accuracy rate of greater than 50%.[14] According to this study, the ability to hit moving targets is a complex learned behaviour, and can be learnt from other members of the school. The study concluded that fish could shoot more accurately after observing other members of the school shooting.[14]

The banded archerfish is able to hit targets with a high degree of accuracy, despite refraction of light at the water-air interface. It was believed that they are able to achieve this level of accuracy by positioning their bodies to shoot from directly under the intended target.[9] However, later studies have found that banded archerfish are able to achieve great accuracy even at angles, suggesting that they are somehow able to compensate for refraction.[14][15] This may also suggest that banded archerfish are capable of three-dimensional tasks.[15]

The shooting behaviour of the banded archerfish is affected by the presence of conspecifics (members of the same species). When conspecifics are visible, this archerfish usually takes longer to shoot, aims more often, and shoots from a closer distance. This is hypothesized to occur to decrease the possibility of kleptoparasitism occurring.[16]

The breeding habits of the banded archerfish are not well known. Banded archerfish first begin to breed when they are about 10 centimetres (3.9 in) long.[9] The banded archerfish reproduces by spawning. There are reports that banded archerfish go to saltwater reefs to spawn, but these have not been confirmed.[17] Archerfish lay 20,000 to 150,000 eggs at a time.[13] Banded archerfish rarely breed in captivity.[10]

Species in the genus Toxotes, including the banded archerfish, are kept as aquarium fish.[2] In aquaria, the banded archerfish can grow up to 25 centimetres (9.8 in) long.[10] They swim at the top level of the aquarium. Banded archerfish can be kept in small groups of three to five;[17] fish of the same size get along but fish that are larger may be aggressive towards those that are smaller,[11] and even try to eat them.[17] They may live from five to eight years in captivity, and occasionally nine or ten. Banded archerfish need warm water, usually between 25 and 30 °C (77 and 86 °F).[11] The aquarium should be large with middling amounts of plant growth and plenty of space for swimming. It should be at least 20 to 30 centimetres (7.9 to 11.8 in) deep.[11]

Banded archerfish are generally not recommended for average home aquaria despite their attractive appearance because they are difficult to care for and require special conditions.[17] Banded archerfish prefer to shoot and capture live food rather than be fed flake food, and are therefore difficult to feed.[11] They need brackish water as well as a tall canopy. In the wild they are able to jump out of the water to capture prey on overhanging branches; a tall canopy is required to prevent their jumping out of the aquarium.[17] Banded archerfish should be kept in an aquarium with a volume of at least 45 to 55 US gallons (170 to 210 L; 37 to 46 imp gal), though a greater volume is preferred.[10] Because of such difficulties in caring for banded archerfish, the species has not yet been successful bred in captivity.[11]