Silver rasbora

About

Found across a broad sweep of Southeast Asia, this mid-sized schooling fish, Rasbora dusonensis, inhabits river systems from the Mekong and Chao Phraya basins down through the Malay Peninsula and into Borneo and Sumatra. In the wild it tends to favor large, slow-moving rivers, often gathering near the surface along shorelines in clear water. Its identity was muddled in scientific literature for several decades until a 2013 redescription sorted it out from closely related species, particularly R. tornieri. The two look very similar, but R. dusonensis can be told apart by its bright yellow tail fin with a broad dark margin, compared to the carmine red of its lookalike. Both share a bold dark brown stripe running the full length of the body from gill plate to tail base, with a second stripe along the upper flank separated by a pale band. In the aquarium it is a peaceful, active fish that does best kept in groups of at least six, where males will spar and display for females in an appealing and natural way. A well-planted tank with some open water for swimming suits it nicely. Its tolerance for a fairly wide range of water conditions and its calm temperament make it a reasonable choice for newer keepers looking to move into slightly larger schooling species.