Franco Banfi / Freshwater Dorado (Salminus brasiliensis) Recanto Ecologico, Rio da Prata, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Serpae Tetra (Hyphessobrycon eques) Recanto Ecologico, Rio da Prata, Bonito, Mato Grosso do Sul, Brazil

Angelo Gandolfi / Piraputanga (Brycon hilarii) fish jumping to catch insects. Bonito, Mato Grosso do Sul, Brazil

Angelo Gandolfi / Spotted Piranhas (Serrasalmus marginatus) Pantanal, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) leaping out of river, Balneario Municipal, Formoso River, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Tourist on the boat feeding Piraputanga (Brycon hilarii) Aqua¡rio Natural, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) Rio Bai­a Bonita, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) in the main spring with people standing on nearby viewing platform, Aqua¡rio Natural that goes in the Rio Bai­a Bonita, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) in the main spring with people standing on nearby viewing platform, Aqua¡rio Natural that goes in the Rio Bai­a Bonita, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) in the main spring Aqua¡rio Natural that goes in the Rio Bai­a Bonita, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) in the main spring Aqua¡rio Natural that goes in the Rio Bai­a Bonita, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) reflecting on the water surface, Aqua¡rio Natural, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) Balneario Municipal, Formoso River, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) Balneario Municipal, Formoso River, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) Balneario Municipal, Formoso River, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) Balneario Municipal, Formoso River, Bonito, Mato Grosso do Sul, Brazil

Franco Banfi / Piraputanga (Brycon hilarii) Balneario Municipal, Formoso River, Bonito, Mato Grosso do Sul, Brazil

Willem Kolvoort / Tetras (Moenkhausia surinamensis) surrounding a mimic (central fish). Near the Awadan, Gran Rio, Suriname, September.

Willem Kolvoort / Poptella longipinnis (long-finned fish) with Aracu (striped fish). Gran Rio, Suriname, September.

Willem Kolvoort / Tetra (Moenkhausia surinamensis) school near river bed. Gran Rio, Suriname, September.

Willem Kolvoort / Tetra (Moenkhausia colletti) (right) and Jupiaba keithi (left). Lokoti creek near Aurora, Suriname, September.

Willem Kolvoort / Unnamed new fish species (Jupiaba polylepis). Gran Rio, Suriname, September.

Willem Kolvoort / Unnamed new fish species (Jupiaba meunieri). The Awadan, Gran Rio, Suriname, September.

Willem Kolvoort / Redtail Bryconops (Bryconops) Gran Rio, Suriname, September.

Piotr Naskrecki / Tetra (Bryconops sp), Suriname

Piotr Naskrecki / Tetra (Hyphessobrycon sp), Suriname

Piotr Naskrecki / Yellow Phantom Tetra (Hyphessobrycon roseus), Suriname

Piotr Naskrecki / Tjongobe (Poptella brevispina), Suriname

Luciano Candisani / Silver Tetra (Tetragonopterus argenteus) school, Pantanal, Brazil

Pete Oxford / Pacu fish (Colossoma macropomum) caught with a bow and arrow, Rewa River, Guyana

Pete Oxford / Giant River Otter (Pteronura brasiliensis) eating Black Piranha (Serrasalmus rhombeus), Karanambu Trust, Rupununi, Guyana

Pete Oxford / Giant River Otter (Pteronura brasiliensis) eating Black Piranha (Serrasalmus rhombeus), Karanambu Trust, Rupununi, Guyana

Pete Oxford / Giant River Otter (Pteronura brasiliensis) eating Black Piranha (Serrasalmus rhombeus), Karanambu Trust, Rupununi, Guyana

Pete Oxford / Giant River Otter (Pteronura brasiliensis) eating Black Piranha (Serrasalmus rhombeus), Karanambu Trust, Rupununi, Guyana

Pete Oxford / Black-tailed Tetra (Hemigrammus levis) young, Rupununi, Guyana

Pete Oxford / Black-tailed Tetra (Hemigrammus levis) school, Rupununi, Guyana

Pete Oxford / Giant River Otter (Pteronura brasiliensis) eating Black Piranha (Serrasalmus rhombeus), Karanambu Trust, Rupununi, Guyana

Pete Oxford / Giant River Otter (Pteronura brasiliensis) eating Black Piranha (Serrasalmus rhombeus), Karanambu Trust, Rupununi, Guyana

Pete Oxford / Giant River Otter (Pteronura brasiliensis) eating Black Piranha (Serrasalmus rhombeus), Karanambu Trust, Rupununi, Guyana

Pete Oxford / Giant River Otter (Pteronura brasiliensis) eating Black Piranha (Serrasalmus rhombeus), Karanambu Trust, Rupununi, Guyana

Pete Oxford / Black Piranha (Serrasalmus rhombeus), Rewa River, Guyana

Pete Oxford / Pirambeba (Serrasalmus sp), Rewa River, Guyana

Pete Oxford / Black Piranha (Serrasalmus rhombeus) eye and teeth, Rewa River, Guyana

Pete Oxford / Pacu (Colossoma macropomum) shot with bow and arow, Rewa River, Guyana

Pete Oxford / Piranha (Cyphocharax sp) group near shore, Rewa River, Guyana

Pete Oxford / Tetra (Characidae) translucent juvenile, native to Central and South America

Mark Moffett / Argentine Ant (Linepithema humile) group eating a piranha on the banks of the Parana River, northern Argentina

Konrad Wothe / Giant River Otter (Pteronura brasiliensis) eating Blacktail Piranha (Pygocentrus piraya), Pantanal, Brazil

Konrad Wothe / Giant River Otter (Pteronura brasiliensis) eating Blacktail Piranha (Pygocentrus piraya), Pantanal, Brazil

Luciano Candisani / Dourado (Salminus brasiliensis) swimming in the Prata River, Cerrado Ecosystem, Brazil

Luciano Candisani / Green Anaconda (Eunectes murinus) constricting a Piraputanga (Brycon microlepis) in small tributary of Formoso River, Cerrado Ecosystem, Brazil

Pete Oxford / Piraputanga (Brycon hilarii) group, Rio de la Plata, Bonito, Brazil

Pete Oxford / Piraputanga (Brycon hilarii) group, Rio de la Plata, Bonito, Brazil

Konrad Wothe / Blacktail Piranha (Pygocentrus piraya)

Claus Meyer / Red-bellied Piranha (Pygocentrus nattereri) portrait, Amazon, Brazil

Konrad Wothe / Blacktail Piranha (Pygocentrus piraya) school

Michael & Patricia Fogden / Black Caiman (Melanosuchus niger) eating a Redeye Piranha (Serrasalmus sp) found in rivers and oxbow lakes, Manu National Park Peru

Konrad Wothe / Giant River Otter (Pteronura brasiliensis) eating Blacktail Piranha (Pygocentrus piraya), Pantanal, Brazil

Luciano Candisani / Piraputanga (Brycon hilarii) feeding on leaf that has fallen into water, Brazil

Luciano Candisani / Piraputanga (Brycon hilarii) feeding on leaf that has fallen into water, Brazil

Luciano Candisani / Fish feeding on Piranha (Cyphocharax sp) eggs attached to aquatic plants, Mato Grosso, Brazil

Luciano Candisani / Dourado (Salminus brasiliensis) protecting territory from rival, Brazil

Luciano Candisani / Dourado (Salminus brasiliensis) in defensive posture, Brazil

Luciano Candisani / Silver Tetra (Tetragonopterus argenteus) in flooded field, Pantanal, Brazil

Michael & Patricia Fogden / Black Caiman (Melanosuchus niger) eating a Redeye Piranha (Serrasalmus sp) found in rivers and oxbow lakes, Manu National Park, Peru

Claus Meyer / Blacktail Piranha (Pygocentrus piraya) vivsection showing teeth, Amazon Basin, Brazil

Michael & Patricia Fogden / Black Caiman (Melanosuchus niger) feeding, Manu National Park, Peru

Franco Banfi / Spotted metynnis (Metynnis maculatus) shoal swimming among aquatic vegetation, Paraguay River, Pantanal, Brazil.

Franco Banfi / Split level view of Piraputanga (Brycon hilarii) shoal swimming close to water surface, surrounded by forest, Aquario Natural, Bonito, Mato Grosso do Sul, Brazil.

Franco Banfi / Split level view of Piraputanga (Brycon hilarii) shoal swimming close to water surface, surrounded by forest, Aquario Natural, Bonito, Mato Grosso do Sul, Brazil.

Franco Banfi / Red-bellied piranha (Pygocentrus nattereri) close up head portrait, showing teeth detail, Pantanal, Mato Grosso, Brazil.

Franco Banfi / Red-bellied piranha (Pygocentrus nattereri) portrait, Pantanal, Mato Grosso, Brazil.

Franco Banfi / RF - Split level view of Piraputanga (Brycon hilarii) shoal swimming close to water surface, surrounded by forest, Aquario Natural, Bonito, Mato Grosso do Sul, Brazil. (This image may be licensed eith...

Franco Banfi / RF - Red-bellied piranha (Pygocentrus nattereri) head portrait, Pantanal, Mato Grosso, Brazil. (This image may be licensed either as rights managed or royalty free.)

Franco Banfi / RF - Red-bellied piranha (Pygocentrus nattereri) portrait, Pantanal, Mato Grosso, Brazil. (This image may be licensed either as rights managed or royalty free.)

Maxime Aliaga / Close up of Red-bellied piranha (Pygocentrus nattereri) after being fished. Pacaya Samiria National Park, Loreto, Peru.

Maxime Aliaga / Red-bellied piranhas (Pygocentrus nattereri) after being fished. Pacaya Samiria National Park, Loreto, Peru.

Joel Sartore / Photo Ark / Black neon tetra (Hyphessobrycon herbertaxelrodi) portrait, Josh'sFrogs. Captive, occurs in Brazil.

Joel Sartore / Photo Ark / Black neon tetra (Hyphessobrycon herbertaxelrodi) portrait, Josh'sFrogs. Captive, occurs in Brazil.

Wim van den Heever / Piraputanga (Brycon hilarii) fish jumping out of water to catch fruit on overhanging branches , Brazil.

Joel Sartore / Photo Ark / Black piranha (Serrasalmus rhombeus) swimming close up, Shark Reef Aquarium. Captive.

Joel Sartore / Photo Ark / Black piranha (Serrasalmus rhombeus) swimming close up, Shark Reef Aquarium. Captive.

Morley Read / Red-eye tetra (Moenkhausia sp) attracted by ripples from Cicada falling into rainforest pond. Pastaza Province, Ecuador.

Philippe Clement / Red-bellied piranha / red piranha (Pygocentrus nattereri / Serrasalmus nattereri) swimming, native to South America. Captive