Sawfish
Sawfish are primarily found in coastal marine and estuarine brackish waters, but they are euryhaline (can adapt to various salinities) and also found in freshwater. The largetooth sawfish, alternatively called the freshwater sawfish, has the greatest affinity for freshwater. For example, it has been reported as far as up the Amazon River and in Lake Nicaragua, and its young spend the first years of their life in freshwater. In contrast, the smalltooth, green and dwarf sawfish typically avoid pure freshwater, but may occasionally move far up rivers, especially during periods when there is an increased salinity. There are reports of narrow sawfish seen far upriver, but these need confirmation and may involve misidentifications of other species of sawfish.
Spring cavefish
The spring cavefish ("Forbesichthys agassizii") is the only member of the genus Forbesichthys and is one of seven species in the family Amblyopsidae. This species is listed as state endangered in Missouri, but it is considered to be of least concern by the IUCN Red List due to its relatively large population size and number of subpopulations. The spring cavefish inhabits caves, springs, spring runs, and spring seeps. It is subterranean, emerging at dusk and retreating underground an hour or two before dawn. The species is located within areas of the central and southeastern United States. It stays underground after dawn, but then emerges into surface waters at dusk. They are a carnivorous fish and are well adapted to their environment. The species' breeding behavior is rarely documented. Spawning occurs underground and in darkness between January and April. The status and distribution of cave-obligate species is incomplete or lacking entirely, which makes conservation and management decisions difficult. Kentucky and Missouri are the two main states that have their agencies managing this species in some way.