If you can find an aquarium that has Archerfish, try really hard to be around during feeding. The "Downtown Aquarium" in Denver has (had?) a tank full of Archerfish, and someone would come and put crickets on the plants overhanging the tank twice a day.
An individual Archerfish takes quite a while to draw a bead on a cricket. The fish very clearly know that the crickets are up in the plants, but it seems like they have to run their aiming algorithm on really slow hardware.
In the Denver Aquarium, there are (were?) quite a number of Archerfish in the tank, 20 or so. Any given spitter did not have room to get the cricket when it hit the surface of the water, but lots of spitters still toook aim at any given cricket. Until I read this article, I was under the impression that Archerfish spat philanthropically, for no immediate reward.
