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 African Jewelfish (Hemichromis bimaculatus), also sold as the jewel cichlid, is a colorful West African cichlid that turns brilliant red when breeding. Found in small streams and canals along Africa's west coast, from southern Guinea to central Liberia....
Overview The Black Molly is a black, captive-bred form of the common molly (Poecilia sphenops). Wild mollies range from Mexico south to Colombia and Venezuela. Grows to about 3.1 in (8 cm). Many black mollies in stores are hybrids with other molly species. Feeding...
Overview The Bolivian Ram (Mikrogeophagus altispinosus) is a peaceful dwarf cichlid. It is also sold as the Bolivian butterfly cichlid. Native to the upper Rio Madeira basin in Bolivia and Brazil. Grows to about 3.1 in (8 cm) standard length. Usually a better choice...
Overview The Convict Cichlid (Amatitlania nigrofasciata) is a hardy Central American cichlid with bold black bars. It is one of the most familiar cichlids in the hobby. Native to Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica and Panama. Grows to about 6 in...
Overview The Discus (Symphysodon aequifasciatus and related Symphysodon species) is a disc-shaped Amazon cichlid prized for its color. Wild fish live in slow tributaries and forest pools along the Rio Solimões and Amazon. Grows to about 6 in (15 cm) long and nearly as...
Overview The Green Swordtail (Xiphophorus hellerii) is the wild-type form of the familiar swordtail. Males grow a long "sword" on the lower tail fin. Native to southeastern Mexico, Guatemala, Belize and Honduras. Grows to about 6 in (14 cm) standard length. The sword...
Overview The German Blue Ram (Mikrogeophagus ramirezi), also called Ramirez's dwarf cichlid or butterfly cichlid, is a small, jewel-like dwarf cichlid. Native to the llanos savanna wetlands of the Orinoco basin in Venezuela and Colombia. Grows to about 1.6 in (4 cm)...
Overview The Endler's Guppy (Poecilia wingei) is a tiny, brilliantly colored livebearer related to the common guppy. Native to lagoons in northeastern Venezuela, such as Laguna de Patos. Males grow to about 1 in (2.5 cm) standard length. Females are larger. Hybridizes...
Overview The Platinum Guppy is a metallic white strain of the common guppy (Poecilia reticulata). Wild guppies come from northeastern South America and the southern Caribbean, including Venezuela, the Guianas and Trinidad. Females grow to about 2.4 in (6 cm). Males...
Overview The Kenyi Cichlid (Pseudotropheus lombardoi, also listed as Maylandia or Metriaclima lombardoi) is a Lake Malawi mbuna. Males are yellow and females are blue with dark bars, which is unusual among mbuna. Found naturally only at the Mbenji Islands and Nkhomo...
Overview The Iridescent Shark (Pangasianodon hypophthalmus) is a large, schooling catfish, not a shark. It was formerly called Pangasius sutchi. Native to the Mekong and Chao Phraya rivers of Southeast Asia. Can reach about 51 in (130 cm) standard length. Sold as...
Overview The Red Wagtail Platy is a red strain of the southern platyfish (Xiphophorus maculatus) with black fins and tail. Wild platies live in streams and rivers on the Atlantic coastal plain of Mexico, Guatemala, Belize and Nicaragua. Grows to about 2 in (5 cm)...
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 Trimac Cichlid (Cichlasoma trimaculatum, also listed as Amphilophus trimaculatus) is a large, colorful Central American cichlid. Native to the Pacific slope of western Mexico, Guatemala and El Salvador. Seriously Fish gives a maximum of 16 in (40 cm)....
Overview The Sailfin Molly (Poecilia latipinna) is a large molly. Males have a tall, sail-like dorsal fin. Native to the southern United States and Mexico, from the Carolinas to Veracruz, often in coastal and brackish waters. Grows to about 5 in (12.5 cm) standard...
Overview The Yucatan Sailfin Molly (Poecilia velifera), also called the giant sailfin molly, is the largest of the sailfin mollies. Mature males carry a huge, sail-shaped dorsal fin. Wild fish come only from southeastern Mexico, in the Yucatán and Quintana Roo region...