Sawfish
Sawfish are mostly found in relatively shallow waters, typically at depths less than , and occasionally less than . Young prefer very shallow places and are often found in water only deep. Sawfish can occur offshore, but are rare deeper than . An unidentified sawfish (either a largetooth or smalltooth sawfish) was captured off Central America at a depth in excess of .
Cavefish
The more than 200 scientifically described obligate cavefish species are found in most continents, but there are strong geographic patterns and the species richness varies. The vast majority of species are found in the tropics or subtropics. Cavefish are strongly linked to regions with karst, which commonly result in underground sinkholes and subterranean rivers.