Tambaqui

The tambaqui is a very big fish.

It lives in warm rivers in South America. This fish has flat teeth. These teeth help it crush seeds and nuts.

It eats fruit that falls in the water. When the fish eats a seed, it carries it away. This helps new plants grow in new places.

The fish can live for a long time. Some can live to be 65 years old!

The tambaqui is a very large fish.

It lives in the warm rivers of South America. This fish is the heaviest characin in the Americas. A characin is a type of fish.

It has a tall body and large eyes. Its teeth are like molars. These flat teeth help it crush seeds and nuts.

Most of its diet is fruit. The fish eats fruit that falls into the water. This helps plants grow in new places. The fish carries seeds away in its gut.

Tambaqui can live for a long time. They can live for 65 years. They often swim in large groups called schools. When the river water has very little oxygen, they can breathe air. They use their gills and other body parts to do this. This helps them survive in many different rivers.

The tambaqui is a huge freshwater fish from South America.

It lives in the warm Amazon and Orinoco basins. This fish is the heaviest characin in the Americas. It is also the second heaviest scaled freshwater fish in South America.

People often call it the black pacu or giant pacu. It is a very important part of the river ecosystem. Many people also keep them in fish farms for food.

This fish has a very special way of eating.

Unlike many other fish, the tambaqui has teeth like molars. These flat teeth help it crush hard seeds and nuts. During the high-water season, most of its diet is fruit. It eats fruits that fall into the water from trees. This helps the fish spread seeds to new places.

This process is a lot like how birds move seeds around.

Scientists have found clues about the tambaqui's long history.

Fossils of this fish come from the Middle Miocene age. These old fossils were found in Colombia and the Peruvian Amazon. This tells us the fish lived in western South America long ago. Back then, the Andes mountains were not as high as they are now. In the Magdalena River, the fish only lives there because humans moved them.

There are many interesting facts about how they live.

A tambaqui can grow to a very large size. They can live for 40 years or even up to 65 years. These fish can also breathe air if the water lacks oxygen. They use their gills and swim bladder to do this.

They can even survive in water with different pH levels. This helps them move between different types of river water.

Understanding the tambaqui helps us learn about the Amazon.

They move in large schools through the flooded forests. They stay in these forests for four to seven months. When the water level drops, they move to main river channels.

Even though they look like piranhas, they are very different. Young tambaqui are often called "vegetarian piranhas" by people. They are a key part of life in the tropical rivers.

The tambaqui, known scientifically as *Colossoma macropomum*, is a massive freshwater fish.

It belongs to the family Serrasalmidae and is native to tropical South America. This species is vital to the ecosystems of the Amazon and Orinoco basins. It is also widely used in aquaculture, which is the farming of aquatic organisms. Because of its size and importance, it is known by many names, including black pacu, giant pacu, and cachama.

The tambaqui has a unique physical design that helps it survive in diverse environments. It is a tall, laterally compressed fish with large eyes and a slightly arched back.

While it looks similar to a piranha, its teeth are very different. Instead of sharp teeth for meat, it has molar-like teeth. These flat teeth are an adaptation for crushing hard plant seeds and nuts. This specialized dentition allows the tambaqui to exploit food sources that other fish cannot. Its color varies based on its habitat, with fish in blackwater rivers appearing much darker than those in whitewater rivers.

This fish follows a specific migratory pattern tied to the seasons. During the non-breeding season, adults live in flooded forests known as várzea, igapó, or clear and blackwater areas. They stay in these forests for four to seven months during the flood season. As water levels drop, they move into main river channels or floodplain lakes. When the next flood season begins, large schools migrate into whitewater rivers to spawn.

They typically spawn between November and February along woody shores or grassy levees. After spawning, the adults return to the flooded forests to repeat the cycle.

The diet of the tambaqui changes significantly depending on the water levels. During the high-water season, the fish relies heavily on fruits and seeds from woody and herbaceous plants. One study showed that fruits made up 78 to 98 percent of their diet during this time.

In contrast, during the low-water season, their diet shifts toward zooplankton. During this period, about 70 percent of their stomach content weight consists of zooplankton, and many fish have empty stomachs. They also consume smaller amounts of insects, snails, shrimps, and decaying plants.

By eating these plants, the tambaqui performs a critical ecological service called seed dispersal. As the fish consumes fruits, the seeds pass through its digestive system. These seeds are then deposited in new locations, much like how birds spread seeds.

Research indicates that the tambaqui consumes about 35 percent of the trees and lianas during the flood season. These seeds can successfully grow once the floodwaters calm down. While the red-bellied pacu is a more efficient disperser, the tambaqui remains a major player in forest regeneration.

The history of the tambaqui can be traced back to the Middle Miocene age.

Fossils of *Colossoma macropomum* have been found in northern Colombia and the Peruvian Amazon. These fossils suggest the species lived in western South America before the Andes mountains rose higher. While fossils exist in the modern Magdalena River basin, the fish only lives there today because humans introduced them. This long history shows how the species has adapted to changing landscapes over millions of years.

Physiologically, the tambaqui is incredibly resilient to harsh conditions. It can survive in environments with very low oxygen by using its gills and the vascularization of its swim bladder to breathe air.

It can also tolerate significant changes in pH levels. Experiments showed that the microbial communities in their guts remain resilient even when pH drops. This ability helps them transition between different types of water streams. However, they are sensitive to salt; salinity levels above 20 g/L result in death.

Today, the tambaqui is an important economic species. Its meat is highly valued in fish markets and is sold both fresh and frozen.

Because they are resistant to disease and can live in low-oxygen water, they are ideal for aquaculture. In Brazil, they are a major farmed species, contributing significantly to the economy. The fish can reach impressive sizes, growing up to 1 meter in length and weighing up to 30 kilograms. They are long-lived animals, regularly reaching 40 years and sometimes living up to 65 years.