Tilapia

Tilapia is a common name for nearly one hundred different species of cichlid fish.

These fish belong to several different tribes, including Coptodonini and Oreochromini. Most tilapia species are native to the freshwater environments of Africa and the Middle East. They typically live in shallow streams, ponds, rivers, and lakes. Some species are also capable of living in brackish water, which is water containing a mix of fresh and salt water. Because they are so hardy, they have become vital to global aquaculture and many artisanal fishing industries.

Physically, tilapia have deep bodies that are laterally compressed, meaning they are flattened from side to side. One of their most unique features is a specialized way of eating. They possess a second set of jaws called pharyngeal jaws located in the throat. These pharyngeal bones are fused into a single structure that bears teeth. A complex system of muscles allows these throat jaws to work alongside the primary mandibles, or true jaws. This division of labor allows tilapia to be highly efficient feeders. They can capture and process a wide variety of different food items.

Tilapia are also famous for a unique parenting behavior known as mouth-brooding. In these species, the parents carry fertilized eggs and very young fish inside their mouths. They hold the offspring there for several days after the yolk sac has been absorbed. This behavior protects the young fish until they are strong enough to survive on their own. This method of care helps ensure that more offspring survive to adulthood. It is a key reason why many tilapia species are so successful in various environments.

Humans have interacted with tilapia for thousands of years. In Ancient Egypt, the fish held deep symbolic meaning. It was represented in hieroglyphs and symbolized rebirth in Egyptian art. The fish was also associated with Hathor, the goddess of fertility and abundance.

In religious history, tilapia is sometimes called "St. Peter's fish." This name comes from a story in the Gospel of Matthew about the apostle Peter. While the text does not name the species, tilapia are found in the Sea of Galilee where the event is said to have happened.

In modern times, tilapia have become a massive part of the global food economy. They are often called "aquatic chickens" because they are easy to farm. Unlike many other fish, tilapia can eat algae or plant-based food rather than other fish. This makes farming them much cheaper and more sustainable. In 2002, the value of farmed tilapia was about US$1.8 billion. China is currently the world's largest producer, yielding 1.3 million tonnes annually.

In the United States, tilapia has been the fourth-most consumed fish since 2002.

To maximize production, farmers often focus on growing only male fish. This is because males grow much faster than females. Farmers achieve this by adding male sex hormones to the food of young fish, or fry. They can also use "supermales," which are fish with specific chromosomes that ensure all offspring are male. This prevents the population from exploding with too many small, unharvestable fish.

This control allows for a stable and predictable harvest of large fish.

However, tilapia can also be a major problem as an invasive species. If they are introduced to new warm-water habitats, they can disrupt local ecosystems. They are included on the IUCN list of the World's Worst Alien Invasive Species. They can crowd out native species or be used to control plants like duckweed.

Fortunately, they cannot survive in temperate, cold-water climates. Most species die if the water temperature drops below 12.8 degrees Celsius. This temperature limit prevents them from invading many parts of the world.