About 89 incidents of spiders that eat fish have been documented by researchers in the U. S., South America and Australia. They came across dozens of spider species on every continent on the planet that catch and eat fish except for Antarctica.

Martin Nyffeler, of the University of Basel in Switzerland, surprised on finding widespread fish-catching behavior geographically and taxonomically across several spider families. On scouring scientific journals and internet, Nyffeler and Bradley Pusey, the University of Western Australia, have discerned few patterns about fish-eating spiders.

They found that these fish-eating spiders prey mostly on insects and fish, especially the ones having size between 0.8 and 2 inches. These spiders, which usually found on the shores of freshwater ponds, streams, rivers and bayous, do not use web to catch their prey.

They sit on top of the water with their hind legs anchored to a stone or a plant and inject their venom into the fish when it comes on surface to breathe in more oxygenated air. The spider pumps a digestive enzyme into its prey and then sucks the dissolved tissue through its mouth opening.

Researchers concluded that the fish-eating spiders generally prey on fish having length two to six centimeters in length. "It's a big-ticket food item with lots of protein and flesh to consume, whereas an invertebrate has lots of hard material that the spider discards", said Bradley.