Apteronotus leptorhynchus (A. macrostomus)

15. September 2023

The “Brown Ghost” is one of the most popular knifefishes in the aquarium. The species is not small, but not huge either: the maximum length to be expected is about 20 cm. This makes it less than half the size of its black cousin (A. albifrons). It is fascinating to observe knifefish in the aquarium. At first they are still shy and hide, but soon the comparatively intelligent fish understand that there is no danger to them in the aquarium. Then they delight the aquarist with their swimming skills, for knifefish can swim forward and backward with equal speed and elegance. All knifefish belong to the electric fish, but they cannot deliver an electric shock, the voltage is much too low for that. The electrical discharges are used by the fish for orientation (like the echolocation of bats on land) and for intra-species communication. In order to avoid electrosmog in the aquarium, each animal needs hiding places in the form of a cave, which shields the electrical signal. Not beautiful, but extremely practical for this purpose are PVC tubes of various diameters.

For decades, the Brown Ghost was believed to have a vast range in South America. In 2013, scientists Carlos David de Santana and Richard P. Vari published a study in which they showed that there is not one widespread species, but that at least nine different species can be identified, each with a relatively small range. Purely externally, however, they cannot be distinguished on live animals. The fish offered in the hobby originate from Colombia and belong with highest probability to Apteronotus macrostomus. This species comes from the surroundings of the city Villavicencio at the Rio Meta, where numerous ornamental fish catchers are active. The “true” A. leptorhynchus is probably not imported; it comes from the Essequibo River drainage in Guyana. However, since there are no significant external differences between the Brown Ghost species, they will probably continue to be referred to as “Apteronotus leptorhynchus” in the trade.

For our customers: the animals have code 208002 on our stocklist. Please note that we only supply to wholesalers.

Text & photos: Frank Schäfer