I’m really excited about today’s animal. I was flipping through my wonderful book of strange animals and one entry had the title ‘water cannon’, with a picture of a fish below it. That was all I needed to see to decide to blog about this animal. Any fish that gets called a water cannon deserves to be written about.
The banded archerfish is a member of the genus Toxotes – a name that means archer in Greek. They can be found in the Indian and Pacific oceans, as well as in rivers and mangrove swamps. The fish can travel through fresh, salt and brackish water, though they prefer to stay in estuaries or in mangrove swamps.
Banded archerfish are medium-sized fish, reaching up to 40 cm long, with an average size of 20 cm. The top of the archerfish is olive-green, while the rest of the body is silver coloured. As its name suggests, the banded archerfish has broad bands on its sides. These are black in colour and can number between four and six. Two notable features of the archerfish are its large eyes that are positioned close to the front of the fish’s head, and the fish’s pointed snout, which is key to the animal’s hunting strategy.
Now is the exciting part – you get to find out why this fish is named the archerfish, why it earned the title water cannon, and why its scientific name means archer. The archerfish has a special way of hunting, that involves take aim and shooting a stream of water at prey above water. The archerfish’s eyes are specially placed to give the fish binocular vision, so it can correctly judge the distance to its prey. The fish is also able to correct for the angle of refraction, as light coming from air to water bends, making shooting prey from below the surface quite a challenge.
When an archerfish has spotted a juicy insect, it puts its snout above water, and then moves its tongue into a special groove in its mouth. The fish then shuts its gill covers quickly, to force water through the groove and up into the air – right at its prey. The fish can shoot multiple times very quickly, and can accurately hit prey 2 to 3 meters away. That’s definitely better than I could do, even if I was throwing something and not shooting water from my mouth. Once the prey has been dislodged from its perch, the archerfish swims over and rapidly catches it, sometimes even jumping out of the water to do so. I guess if you have to work that hard to get prey, you don’t want to waste it.
I bet it would be really neat to see archerfish hunting for prey – all you’d see from the surface is steams of water seemingly coming from nowhere. It’d be especially great if you found a school of young fish – they school together and all shoot at a target because their aim isn’t that great yet. Still, I’d be satisfied with just seeing one in action, as long as it didn’t shoot water at me!
Cover photo By Cangadoba – Own work, CC BY-SA 4.0