Though the Silver and Black arowanas of South America, and the Asian and Australian arowanas resemble each other, and share the behavior of brooding their eggs and fry in their mouths, they last shared a common ancestor around 170 million years ago, when the great Southern Continent Gondwana began to split apart. This took place in the Jurassic period, when dinosaurs still thrived. Although Asian arowanas are endangered, South American ones are abundant, and are important both to subsistence fishing and the sustainable aquarium trade.
It appears there are no documented cases of piranhas killing people, but there have been several cases where they have eaten humans that had drowned. In general, these specialized relatives of the tetras are opportunistic scavengers. Of the 50 or so species found in South American Rivers, this one is the most familiar, and is popular in aquariums for its bright colors. If maintained in groups of less than four, piranhas are likely to eventually kill each other. They have been bred many times in captivity.
Growing to a foot in length, this eye-catching relative of tetras and piranhas is a typical inhabitant on flooded forests in South America. For more than 50 years it has been very popular in the pet trade. While having a reputation for harassing other fishes in home aquariums, it is not aggressive in roomy accommodations.
The various shovel-nosed catfishes of South America are popular inhabitants of large aquariums and important food fishes in their native rivers. As their huge mouths would suggest, they are active predators, hunting for others fishes and crustaceans at night. They easily grow to over three feet.
No relation to sturgeons, this huge relative of the little “talking catfishes” (popular with aquarists) possesses similar looking bony scutes along its side, giving it a prehistoric appearance. One of its other aquarium shop names is in fact “Prehistoric catfish” and another is “Ripsaw”. Though exceeding three feet in length, they feed almost entirely on invertebrates and detritus, as one might deduce from their small mouths.
All of the many Red-tailed catfish at the DWA are donations from aquarists whose tanks they rapidly outgrew. Popular in the pet trade since the 1960s, this widespread South American fish is often sold at a length of two inches, but may eventually reach five feet and weigh over 100 pounds, potentially eating anything it can swallow.
Called Arapaima in the Guianas, Paiche in Peru, and Pirarucu in Brazil, this relative of the arowana is one of the largest purely freshwater fishes in the world, reaching nine feet and exceeding 400 pounds. They have been overexploited as food fishes, so are vulnerable to extinction. These fast-growing predators surface frequently to take air at the surface. While aquarium visitors may mistake them for Alligator gars, they are not related. Their closest North American relatives are the herring-like Mooneyes and Goldeneyes.
The Tiger rockfish is named for its striped coloration. The rockfish family is one of the largest fish families found in the temperate waters of the Pacific coast of North America. Its natural range extends from Alaska to Central California and it is known to be territorial and solitary. Many members of the rockfish family have venomous dorsal spines. The Tiger rockfish prefers to hide in rocky crevices and feeds on small crustaceans and fish.