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 One of the most popular and recognizable aquarium fish. Lives in acidic forest streams, often stained with tannins (blackwater), with leaf litter and roots. Has a bright blue lateral stripe. The red pigment does not extend forward past the pectoral-fin base....
Overview The Black Angelfish is a solid black color form of the freshwater angelfish (Pterophyllum scalare). Wild angelfish come from the Amazon basin in Brazil, Peru and Colombia, and from the Guianas. Grows to about 6 in (15 cm) long and taller with the fins, so it...
Overview The Black Phantom Tetra (Hyphessobrycon megalopterus) is a peaceful, smoky-gray tetra with a black shoulder spot and large fins. Native to the upper Rio Madeira basin in Bolivia and western Brazil, and the Rio Paraguay basin. Grows to about 1.4 in (3.6 cm)...
Overview The Black Skirt Tetra (Gymnocorymbus ternetzi), also known as the Black Widow Tetra, is a hardy, deep-bodied tetra with black vertical bars and a dark rear half. Native to slow creeks and streams with overhanging plants in the Paraguay and Guaporé basins of...
Overview The Bloodfin Tetra (Aphyocharax anisitsi) is a silvery tetra with bright red fins. Native to the Paraná River basin in Brazil, Paraguay and Argentina. Grows to about 2.2 in (5.5 cm) standard length. A hardy beginner fish that adapts to a wide range of...
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 Cardinal Tetra (Paracheirodon axelrodi) has a neon-blue stripe above a red lower body that runs the full length of the body. Native to forest streams in the Rio Negro and upper Orinoco basins of Brazil, Colombia and Venezuela. Grows to about 1.4 in (3.5...
Overview The Duboisi Cichlid (Tropheus duboisi), or white-spotted cichlid, is a Lake Tanganyika cichlid. Juveniles are black with white spots and adults develop a pale band. Lives in rocky areas, in deeper water than other Tropheus. Grows to about 5 in (12 cm)...
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 Colombian Tetra (Hyphessobrycon columbianus) is a robust tetra with a blue-silver body and red fins. It is also sold as the blue-red or Colombian red fin tetra. Known only from the Río Acandí area in northern Colombia, near the Panama border. Grows to...
Overview The Harlequin Rasbora (Trigonostigma heteromorpha) is a classic schooling fish with a copper body and a black triangle on the rear half. Native to southern Thailand, Peninsular Malaysia, Singapore, Sumatra and Borneo. Grows to about 1.8 in (4.5 cm) standard...
Overview The Cockatoo Dwarf Cichlid (Apistogramma cacatuoides) is a hardy South American dwarf cichlid named for the male's tall, crest-like dorsal fin. Widespread in the upper Amazon basin, in slow tributaries, backwaters and creeks with leaf litter. Males reach...
Overview The Glowlight Rasbora (Trigonopoma pauciperforatum), also sold as the redline rasbora, is a slim rasbora with a glowing orange-to-gold stripe. Native to Peninsular Malaysia, Singapore, Sumatra and Borneo. Grows to about 2.4 in (6 cm) standard length. Lives in...
Overview The Glowlight Tetra (Hemigrammus erythrozonus) is a small, peaceful tetra with a glowing orange-red stripe. Known only from the Rio Essequibo in Guyana. Grows to about 1.6 in (4 cm) standard length. All fish sold are commercially farmed. An albino form is...
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 Fairy Cichlid (Neolamprologus brichardi), also known as the Princess of Burundi, is an elegant Lake Tanganyika cichlid with long, white-edged fins. Found along the rocky shores of Burundi, Tanzania and the Democratic Republic of the Congo, mostly 16–82 ft...
Overview The Firemouth Cichlid (Thorichthys meeki) is a Central American cichlid known for its bright red-orange throat, which it flares to display. Native to lowland waters from southeastern Mexico, around the Yucatán Peninsula, to northern Belize and Guatemala....
Overview The Espe's Rasbora (Trigonostigma espei), also called the false harlequin or lambchop rasbora, is a small copper-orange rasbora with a black wedge mark. Native to forest streams in southwestern and southeastern Thailand and nearby Cambodia. Grows to about 1.2...
Overview The Electric Yellow Cichlid (Labidochromis caeruleus) is a bright yellow mbuna from Lake Malawi. The yellow form comes from a short stretch of the northwestern shore, between Charo and Lion's Cove. Grows to about 3.9 in (10 cm) standard length. One of the...
Overview The Pindani Cichlid (Pseudotropheus socolofi), also called Eduard's mbuna, is a powder-blue Lake Malawi mbuna. Native to the Mozambique coast of Lake Malawi, between Cobue and Tumbi Point. Grows to about 5 in (11.5 cm) standard length. An albino form is also...
Overview The Pearl Cichlid (Geophagus brasiliensis), also called the pearlscale or mother-of-pearl cichlid, is a robust eartheater with iridescent spangled scales. Native to coastal rivers of eastern and southern Brazil and Uruguay. Grows to about 10 in (25 cm)...
Overview The Paraguay Eartheater (Gymnogeophagus balzanii) is a hump-headed South American cichlid that sifts sand for food. Native to the Paraná and Uruguay basins in Brazil, Paraguay, Argentina and Uruguay. Grows to about 8 in (20 cm) standard length. Best for...
Overview The Mexican Tetra (Astyanax mexicanus) is best known in its blind cave form, the blind cave tetra. The species ranges from Texas and New Mexico through Mexico to Guatemala. The eyeless form lives only in Mexican caves. Grows to about 3.7 in (9.5 cm) standard...
Overview The Kribensis (Pelvicachromis pulcher), or krib, is a colorful West African dwarf cichlid. Females show a cherry-red belly. Native to Nigeria and Cameroon, in still and slow, heavily vegetated waters. Grows to about 3.9 in (10 cm) standard length. Most fish...
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 Shoulder Severum (Heros sp. "Rotkeil") is a severum from Brazil with a red patch behind the gills. Its exact identity is unclear. It is often linked to Heros efasciatus. Severums in general come from slow rivers and floodplain lakes of the Amazon....
Overview The X-Ray Tetra (Pristella maxillaris) is a semi-transparent tetra with black, yellow and white fin markings. Native to coastal waters of Venezuela, the Guianas and northern Brazil. Grows to about 1.8 in (4.5 cm) standard length. Commercially bred and one of...
Overview The Serpae Tetra (Hyphessobrycon eques), also called the jewel or callistus tetra, is a red tetra with a black shoulder spot. Found through much of the Amazon and the Río Paraguay. Grows to about 1.6 in (4 cm) standard length. Feeding Likely omnivorous....