The giant freshwater stingray may be the world’s largest freshwater fish. It’s also cloaked ... Experts, however, stress that the rays are non-aggressive and inquisitive.
Oscars are an aggressive and highly intelligent freshwater fish hailing from South America, specifically the tropical Amazon River Basin and its tributaries. They go by many names, including ...
A diminutive but aggressive predator, the three-spined stickleback hunts tadpoles and small fish. It is also known for fiercely protecting its nest of ... Marine three-spined sticklebacks migrate out ...