Sawfish
The dwarf and largetooth sawfish are strictly warm-water species that generally live in waters that are and respectively. The green and smalltooth sawfish also occur in colder waters, in the latter down to , as illustrated by their (original) distributions that ranged further north and south of the strictly warm-water species. Sawfish are bottom-dwellers, but in captivity it has been noted that at least the largetooth and green sawfish readily take food from the water surface. Sawfish are mostly found in places with soft bottoms such as mud or sand, but may also occur over hard rocky bottoms or at coral reefs. They are often found in areas with seagrass or mangrove.
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.