Predation is a way of preying on and eating animals that is based on preying on and eating other animals.

Predatory fish - a group of fish whose main source of food is fish or other food of animal origin (pike, taimen, nelma, ssak. burbot). They are carnivorous fish that prey on other fish or aquatic animals.

In 2003, populations of large predatory fish in the world's oceans were about 10% of their pre-industrial levels. These are the species most at risk of extinction. During the Cretaceous-Paleogene extinction event 66 million years ago, large predatory fish died out at a disproportionately high rate. The establishment of marine protected areas has been shown to restore populations of large predatory fish such as serranidae - groupers and sea bass.

Predatory fish switch between prey types in response to fluctuations in prey abundance. These changes in preference are disproportionate and are considered evolutionarily efficient. Predatory fish can become pests when introduced into an ecosystem where they become the new top predators. An example that has caused many problems in Maryland and Florida is the snakehead fish.

Predatory fish such as sharks, mahi-mahi, marlins and tuna form part of the human diet and are targeted by fisheries.

Predatory fish - pike, perch, catfish, mackerel and tuna - are more likely than "peaceful" fish to accumulate mercury at levels dangerous to humans. While the norm for mercury in the body of "peaceful" fish is 0.3 mg per kilogram of raw weight, the norm for predatory fish is 0.6 mg/kg.