Answer:
They are primarily bottom dwellers and feeders. There are hundreds of species that live in all different marine environments - freshwater, salt, brackish, creeks, rivers, and ponds. Further north, the only additional requirement is that the water be deep enough that they can survive beneath the ice sheet. The hide from predators and are most commonly found near rocks, grasses, or mud in the water. Some species burrow or tunnel into the muddy banks and beds, even leaving the water to bury themselves at the edge to further protect themselves, particularly pregnant females.