Archerfish

Geographic Origin and Biotope: Indo-Pacific Ocean and Southeast Asia (India to Australia). Inhabits huge tidal mangrove estuaries, but unlike others, it pushes hundreds of kilometers inland into purely freshwater rivers.

Taxonomy and Morphology: Largescale Archerfish (Toxotes chatareus). It possesses the famous modified mouth (the palate has a deep groove used as a "gun barrel" in combination with the tongue) and large binocular eyes positioned almost on the snout.

Social Behavior: The water sniper. Gregarious as a juvenile, in adulthood (35 cm / 14 inches!) it becomes solitary. Spends its life peering over the surface of the water. If it spots an insect on a leaf outside the aquarium, it shoots a perfect jet of water (which also calculates light refraction) hitting it and knocking it down.

Coloration and Sexual Dimorphism: Shiny silver/olive green background (not to be seen from below). Compared to the common Archerfish (jaculatrix) which has separate black bands, the chatareus features conspicuous black spots or bands that join in a checkerboard pattern on the back. There is no dimorphism.

Aquarium Setup: Huge Paludarium Aquarium (Minimum 150 cm / 60 inches x 70H). This fish makes no sense in a filled closed tank. It needs a Paludarium: fill only half the tank (25 cm / 10 inches) with water and leave huge emerged mangrove branches where to trigger its predatory behavior (shoot jets for 1-2 meters / 3-6 ft).

Diet and Feeding: Hunting Insectivore. Eats 90% of the time insects and spiders that fall or that it "shoots down" from the vegetation. In captivity, stick mealworms or crickets on branches out of the water to make it "shoot" and make it happy. Eats pellets only as a fallback.

Water Quality: Euryhaline and tolerant. The chatareus tolerates indistinctly hard freshwater or heavily brackish water, but produces a considerable load of waste. Robust filtration but without violent surface currents (so as not to disturb its "aim").

Compatibility and Tankmates: To be paired with medium/large tankmates in brackish water (Scatophagus, Monodactylus). Mercilessly devours any small fish (Guppy) that crosses its path near the surface. Can fight fiercely with conspecifics if in limited space.

Aquarium Reproduction: Never documented in home systems, except through hormonal induction in gigantic lagoons in Asia.

Risks and Diseases: Lid Blindness. The most fatal mistake: keeping it in a 200L (50G) tank closed to the brim with a plastic/glass lid at the water level. The fish will constantly bang its lips trying to "shoot" the light fixture (or reflections), stressing itself out and developing abrasions on the snout or cataracts (infections) that will condemn it to death.