What is "northern cavefish"

n. 1 (context uncountable English) A species of fish, (taxlink Amblyopsis spelaea species noshow=1). 2 (context countable English) A fish of this species.

The northern cavefish or northern blindfish, Amblyopsis spelaea, is found in caves through Kentucky and southern Indiana. It is listed as a threatened species in the United States and the IUCN lists the species as vulnerable.

During a 2013 study of Amblyopsis spelaea, scientists found that the species was divided into two distinct evolutionary lineages: one north of the Ohio River, in Indiana, and one south of the river, in Kentucky. The southern population retained the name A. spelaea and the northern was re-designated Amblyopsis hoosieri in a 2014 paper published in the journal ZooKeys. Neither species is found north of the White River, flowing east to west south of Bedford, Indiana.