The menu of fish is rich and varied. Why do not they eat fish! Take, for example, predators, fish-eaters: some of them eat only small fish, others swallow prey no less, or even more of their own weight. Pike, a thunderstorm of Siberian waters taimen sometimes does not mind eating a duck or a squirrel swimming in the river. In the stomach of sharks find pieces of ruptured dolphins, and in the beluga stomachs whole swallowed seals come across.
There are gastronomes among fish: one only serve crabs, crayfish, shrimp, others – oysters and other tender shellfish. Many fish have their favorite dish – insects. There are fish that feed on one plankton – the smallest animals and plant organisms, and there are inveterate vegetarians – they only eat plants. Yes all that eat fish, and do not list.
The catch of fish is grasped with the mouth. And the mouth, convenient for catching fish, is not suitable for collecting mollusks or plucking shoots of aquatic plants. Therefore, the device of the mouth in different fish is not the same.
Predatory fish, as a rule, have a large mouth and long, sharp, often bent back teeth. Teeth help to grab and hold prey. At smelt, soft teeth, the teeth are even in the tongue, but in the pike in the sky, and the palatine teeth of the pike can be pressed back to make it easier to swallow the prey.
Most predatory fish teeth are periodically replaced with new ones. Fish change them as they wear out, and the change of teeth for each individual fish occurs at different times. Therefore, the widespread opinion among fishermen that pikes do not take bait due to the change of teeth at any particular time of the year is not justified.
Predators, which, in addition to fish, eat and mollusks, have two types of teeth. For example, in the commercial fish of the Barents and White Seas, wolffish, the anterior teeth are conical and serve to grasp the prey, and lateral and posterior flat ones for crushing shells of mollusks, echinoderms, sea stars. Special teeth for cracking shells and corals are in tetradontos, spinogs, and bodybuilders. Their teeth form a kind of beak with sharp cutting edges. The ravines straighten out with mollusks flat, like plates, with teeth. And in carp fish – carp, asp and others – there is no teeth in the mouth at all. Their teeth are located in the throat. Together with a dense horn-shaped millstone, they chop and grind food.