Blax’s Longtail Knifefish (Archolaemus blax)

Blax’s Longtail Knifefish (also sometimes known as the Rat Tail Knifefish)  is an active, large-growing species known from the Rio Tocantins and other lower Amazon tributaries in Brazil. In the aquarium, this is a relatively hardy knifefish but like most of their relatives will do best in somewhat soft water and require plenty of hiding places in the form of driftwood, plants or caves. As a fairly active swimmer, this knifefish should also be provided plenty of open swimming space. They will readily accept most frozen and prepared foods and while not typically aggressive towards tankmates they will likely prey on very small fish or invertebrates.