Archerfish (Toxotes chatareus)
Rivaling the mudskipper in uniqueness is another inhabitant of warm brackish waters, the archerfish. In the case of this interesting animal, the unique talent is the ability to knock insect prey from overhanging branches with a well aimed jet of water.
There are six species of archerfish, the largest of which reaches a length of 16 inches. They are found throughout the Indo-Australian region, most commonly in association with mangrove swamps. Although most are creatures of shallow, coastal areas, some do enter freshwater environments as well.
Archerfish have developed a quite interesting method of securing their food. They spend most of their time scanning overhanging branches for insects. When a potential target is sighted, the fish stops, takes aim, and quite forcibly ejects a stream of water at the insect. The fish rarely misses, and the dislodged insect falls into the water and is consumed. The archerfish accomplishes this amazing feat by compressing its oral cavity and pressing the tongue against the grooved palate. These contractions force the water out of the mouth. The archerfish must allow for the distortion of light as it appears in the water when taking aim at its prey. The environments inhabited by the archerfish are home to an enormous number of insect-eating animals that compete with it for food. In such situations, animals often develop ways of exploiting food sources unavailable to similar creatures.
When opening your aquarium's lid to feed your archerfish, do not be surprised if they immediately stop swimming and begin focusing on you. In many cases, they will take aim at your eyes and will quite accurately squirt water at the movement they detect there!
Archerfish will do well in a typical brackish water aquarium set up. However, it seems a shame to house these unusual fish in a situation that does not allow for the use of their unique abilities. They are better exhibited in an aquarium that is half filled with water, over which has been positioned tree branches and plants. The set up as described earlier for keeping mudskippers will accommodate archers as well.
Archerfish thrive at water aquariums at temperatures of approximately 75°F (24°C). They can tolerate and even seem to benefit from fluctuations in salinity. They are very active and should be given as much room as possible. Archerfish get along fairly well with each other and with similarly sized species. Archers are quite accomplished jumpers, so their aquarium should be well covered.
Although they are insect specialists, archerfish have expansive appetites and will readily consume all manner of fish foods. They do, however, relish live insects and will put on quite a show if crickets are released onto the branches overhanging their aquariums. Archers will also benefit from occasional meals of wild caught invertebrates such as grasshoppers, moths, small spiders, beetles, and earthworms.
Archerfish are aggressive feeders and will quickly out-compete most other tank mates. Therefore, pay particular attention to each individual at feeding time.