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 Clown Knifefish (Chitala ornata) is a large, nocturnal predator with a row of black spots along its knife-shaped body. Native to the Mekong, Chao Phraya and Mae Klong basins of Thailand, Laos, Cambodia and Vietnam. Can reach about 39 in (100 cm), far too...
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 "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 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 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 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...