Here are some of the most popular freshwater fish species that are commonly kept in aquariums, each with unique characteristics and care requirements.
A common rule of thumb for how many freshwater fish you can keep in an aquarium is to allow about 1 inch of fish per gallon of water; however, this can vary depending on the specific fish species, their adult size, activity level, and bioload, with heavily planted or densely stocked tanks often needing more filtration and swimming room.
Overview The Bronze Cory (Corydoras aeneus) is one of the best-known catfish in the hobby. Wild fish range across much of South America, from Trinidad to Argentina. Grows to about 3 in (7.5 cm) standard length. Albino and long-finned forms are bred. The origin of...
Overview "Gold Piranha" is a trade name for Serrasalmus maculatus, also called the golden mac. The name is sometimes applied to other Serrasalmus species. Widespread in the Amazon, Paraguay and Paraná basins of South America. Grows to about 8 in (21 cm) standard...
Overview The Peppered Cory (Corydoras paleatus) is a hardy, mottled gray-green catfish and one of the first cories kept in aquariums. Native to southern Brazil, Uruguay, Paraguay and Argentina. Grows to about 2.8 in (7 cm) standard length. Feeding An opportunistic...
Overview The Panda Cory (Corydoras panda, also placed in Hoplisoma) is a small white catfish with black eye and tail patches. Native to the upper Amazon in Peru, in clear and blackwater streams over sand. Grows to about 2 in (5 cm) standard length. Almost all fish...
Overview The Julii Cory (Corydoras julii, now sometimes placed in Hoplisoma) is a small catfish with a fine leopard-spot pattern. Native to coastal rivers south of the Amazon delta in northeastern Brazil. Grows to about 2.2 in (5.5 cm) standard length. Many fish sold...
Overview The Red-bellied Piranha (Pygocentrus nattereri) is the most famous piranha, silver with a red belly. Found through much of the Amazon basin, plus the Essequibo and the Paraná–Paraguay system. Grows to about 14 in (35 cm) standard length. Illegal to own in...
Overview The Zebra Danio (Danio rerio) is a hardy, blue-and-gold striped cyprinid, also known as the zebrafish. Native to the Ganges basin and nearby areas of northern India and surrounding countries. Grows to about 2 in (5 cm) standard length. Long-finned and other...
Overview The Sterbai Cory (Corydoras sterbai, also placed in Hoplisoma) is a spotted catfish with orange pectoral fins. Native to the Rio Guaporé area of Bolivia and Brazil. Grows to about 2.6 in (6.5 cm) standard length. Almost all fish sold are commercially bred....
Overview The Three Stripe Cory (Corydoras trilineatus, also placed in Hoplisoma) is a patterned cory often sold as the julii cory. Found in the Amazon basin in Colombia, Peru and Brazil, and coastal rivers of Suriname. Grows to about 2.2 in (5.5 cm) standard length....