The Black Pacu (Colossoma macropomum) is a large species of freshwater fish in the family Serrasalmidae. The Black Pacu is the heaviest characin in the Americas (the lighter Salminus can grow longer) and the second heaviest scaled freshwater fish in South America (after the arapaima) It is similar in shape to the piranha and juveniles are sometimes confused with the carnivorous fish; the Black Pacu is tall and laterally compressed with large eyes and a slightly arched back.
The iridescent shark (Pangasianodon hypophthalmus) is a species of shark catfish (family Pangasiidae) native to the rivers of Southeast Asia. It is not a shark. It is found in the Mekong basin as well as the Chao Phraya River. Its striking shark like appearance (as it is actually a catfish) and iridescence have made it popular freshwater fish with divers.
The oscar (Astronotus ocellatus) is a species of fish from the cichlid family known under a variety of common names, including tiger oscar, velvet cichlid, and marble cichlid. The species is also able to rapidly alter its colouration, a trait which facilitates ritualised territorial and combat behaviours amongst conspecifics. Juvenile oscars have a different colouration from adults, and are striped with white and orange wavy bands and have spotted heads.
