The pirhana is a predator type of fish, which is very well known for their permanent appetite for meat and for their unusually sharp teeth. The image of pirhanas has been used for many years in a variety of occurrences, which have made them popular even in the regions where their apparition is improbable. The rivers of the South American countries are the main homes of these fish. They can be found in the Amazon basin, in the San Francisco River, in the Paraguay-Paraná, in the rivers of the Guyana and so on. Pirhanas kept in aquariums can be seen in many more locations.

The usage of the pirhanas for the humans is a very complex one. There are many ways through which their capture can be valued in various ways. From the products that can be taken out of the fish, we can count as main elements the teeth. Due to the fact that they are very small, but have high power of resistance and strength, the teeth have been used in the construction of a variety of tools by the indigenous population, which still remain in usage or on various commercial displays today. In some of the regions in which fishermen stake out for pirhanas, these are also cooked and eaten. However, these occasions have the tendency to be rare, due to the fact that the ones that get caught bite everything around them, including nets and other tools. In the mean time, they tend to steal the bait of the fishermen, to mutilate the catch and to damage all the items that stand in their way.

One of the most interesting developments with the usage of the pirhana is the one in the industry of souvenirs. Most of the times, pirhanas are dried out and emptied for the creation of a certain decorative piece. These items, although rather weird looking, are very attractive and fascinating for tourists looking to have even the most bizarre memories of the places they have seen in their vacations. There are some areas in which people can buy a pirhana as a pet, but this is an illegal practice mostly. However, even in the regions where it is allowed, the issue of taking care of these fish is extremely difficult, due to the fact that they can become very aggressive and even cannibalistic when kept in small spaces.