Sawshark
The Bahamas sawsharks ("Pristiophorus schroeder") have very little information on them. Studies are being done daily to learn more about the deep sea dweller. They are located near Cuba, Florida, and the Bahamas (hence their name) where they dwell in the depths of 400–1000 m. As far as their appearance they can be identified by their snouts with teeth which appear as a saw, as well as their length, they are averaged at 80 cm in length.
Saw sharks and sawfish are cartilaginous fish possessing large saws. These are the only two fish that have a long blade-like snout. Although they are similar in appearances, saw sharks are distinct from sawfish. Sawfish are not sharks, but a type of ray. The gill slits of the sawfishes are positioned on the underside like a ray, but the gill slits of the saw shark are positioned on the side like a shark. Sawfish can have a much larger size, lack barbels, and have evenly sized teeth rather than alternating teeth of the saw shark. Clear difference is that a sawfish has no barbels and a saw shark has a prominent pair halfway along the saw. The saw shark uses these like other bottom fish, as a kind of antennae, feeling the way along the ocean bottom until it finds some prey of interest. Both the saw shark and the sawfish utilize the electroreceptors on the saw, ampullae of Lorenzini, to detect the electric field given off by buried prey.
Banded pygmy sunfish
The banded pygmy sunfish is a dwarf fish that can live in rivers, streams, lakes, ponds, and even swamps. This species is historically found only in the continental United States, with relatively little change in distribution. One exception to this is minor decreases in species distribution due to habitat loss. They have historically been residents of the Mississippi River drainage system and Gulf coastal plain region. Currently, they are found from the lower Roanoke River drainage in North Carolina to the southern to middle parts of the St. Johns River in Florida. Also, they are found west to the Brazos River drainage in Texas and north to lower Wabash River drainage in Indiana and Illinois. Being a member of Elassomatidae, this species of pygmy sunfishes is no different in habitat preferences. It prefers to live in slower to still water conditions with higher sedimentation content, hence the swamps and ponds. However, the human development of wetland habitat over the ages has caused a decrease in banded pygmy sunfish and other pygmy sunfish habitat. Though the banded pygmy sunfish can retreat to lakes, streams, and rivers when wetlands are being drained, they need the wetlands for breeding. Thus, the true reason for the disappearance of the banded pygmy sunfish from certain areas is not just a loss of any habitat, but the loss of its breeding habitat. When this happens, the population eventually dies off, leaving an area that can no longer support the species.