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...