Archerfish

by: Andrew Booth, (aka Fish_Tank), Marlborough Aquarium Club, Jnr member

The Archerfish, Toxotes jaculatrix, is famous all over the world for its shooting capabilities. In fact, Toxotes means ”bowman” or ”archer”. Because they are so ”famous” many people will see them in their local aquarium shop and say ”Ohhhhhh, look at those cute little archerfish, I bet a few of them will go well in that spare 2ft tank we have.” We all want to care for our fish properly, so lets take a closer look at this intriguing species.

How do they shoot?

Let’s explore this first. Because of their narrow profile, their prey find it hard to see them and they can sneak into shooting range quite easily. Once into position, the archerfish acts like an underwater water pistol and ”spits” a strong jet of water at their prey. They do this by putting their tongue against a groove in their mouth, forming a tube, and powerfully forcing water out by snapping shut their gills. To get a decent jet of water, they stick their snout slightly out of water, but the rest of the fish remains submerged. They direct their “shot” with their tongue, and they have large eyes located near their mouth, giving excellent binocular vision.
Surprisingly, their eyes do not automatically correct for refraction and they have to learn how to do this. The area of least distortion is directly below their prey, and the young archerfish quickly learn that this is the best place to shoot. They can shoot 6-7 times in quick succession, and the jet can get over 2-3m high, but they lose accuracy after 1m. Juveniles as small as 2-3cm in length can already ”shoot”, but their jet only reaches about 10-20cm.
The archerfish prefers to leap out of the water and grab their prey in their jaws when it is close enough. They can leap up to 30cm high to catch their prey. When this fails, they will resort to shooting. They often swim around in “shooting parties”. Often several fish will relentlessly shoot at the same prey. When the prey finally falls they will all rush in to grab it. Because the sharp shoot doesn't always collect the “prize”, the archerfish prefers to leap up and grab the prey when it is within reach. I guess food in the mouth is better than shooting for nothing but they don't always eat “above water” prey, in fact they often eat underwater creatures and fishes, sometimes swimming deeper to catch them.

Breeding

Captive breeding has been accomplished accidentally on a few occasions. The pair spawns close to the surface and about 3000 floating eggs are laid. The eggs should be transferred to a rearing tank where they hatch in 12 hours. Feed the young small insects and live food that can be taken from water surface. It is believed that in the wild the more solitary adult fish will head out to coral reefs to breed, while the smaller juveniles will form groups in the brackish mangrove swamps of southeast Asia and Australia.

Archers in the aquarium

To keep archerfish, you'll want to devote a fairly large aquarium to them, preferably 200l+. It is best to fill the tank about ¾ full, and grow plants that will tolerate brackish conditions, and grow out of the water (species?).
Another good idea is to have some branches etc out of the water. A tight fitting lid is advisable because not only are they good jumpers, you may want to put live insects, like crickets, in for them to shoot down.

Water conditions

pH; 7-8 (7.5)
dH; 10-18 (12)
temperature; 25-31°C
A 1-2% addition of salt is required. Add 7.5-15 tsp. of salt to every 10 gallons (10-20 g/10 L).

Archerfish make an excellent addition to a brackish community, but they do get to a decent size (up to 30cm in length). Avoid mixing large specimens with small specimens as the larger ones will bully the smaller fish.

Enjoy your archerfish!