Brown ghost knifefish

The brown ghost knifefish (Apteronotus leptorhynchus) is a species of weakly electric knifefish in the family Apteronotidae. The brown ghost knifefish is the only vertebrate proven to have negligible brain aging thus far. As such, they are extensively researched as a model species for neurological and developmental studies. In the wild, A. leptorhynchus is understudied known only to inhabit deep channels of large, lowland rivers, specifically the Essequibo River drainage in Guyana, where it is active nocturnally and seeks vegetated retreat sites during the day. They are listed as an endangered species by the ICUN.