A favored feeding site is often the head of the pool, where a trout will have the first chance to seize insects or other organisms carried into the pool. It also has the option of hunting many of the forms of life that live in the stream with it: insect larvae and nymphs of many kinds, aquatic beetles and spiders, crayfish, leeches and worms, water-mites, snails, salamanders, tadpoles, and the smaller fish. Among the more common fishes that live in rainbow trout territory in low elevation, low gradient streams are sculpins, dace, hogsuckers, river chubs, shiners, and stonerollers. Hogsuckers, which reach 30 centimeters (a foot) or more in length, can be seen in many large, quiet pools. There they search for food on the bottom with their downward protruding lips. Dace and shiners, members of the minnow family, are very small fish and some species are brilliantly colored. The river chub and stoneroller, also minnows, are larger; the stoneroller occasionally reaches 28 centimeters (11 inches). Locally known as “hornyhead” and enjoyed as a food fish, the abundant stoneroller may limit the numbers of rainbow trout in some stretches of stream because of its own spawning activities. Rainbows lay their eggs on gravelly areas in early spring. A month or so later, before the trout eggs have hatched, stonerollers frequently build their nests in the same places, covering or scattering the trout eggs in the process. This sort of competition was probably not expected or considered when rainbows were introduced to the Smokies; nevertheless, the trout do manage to perpetuate themselves. No doubt the most peculiar creature in the lower sections of park streams is the hellbender, a huge, grayish salamander with a loose fold of skin along each side. Commonly reaching 30 centimeters (a foot) and occasionally more than 60 centimeters (2 feet) in length, hellbenders hide under rocks and debris in swift water and feed on fish and other animals up to the size of crayfish. Below elevations of about 500 meters (1,600 feet) smallmouth bass, rock bass, and brightly colored little darters appear in park waters. Brown trout, an introduced species that has apparently entered the park from farther downstream, live in the lower sections of some streams, and may be found in the headwaters of some streams. Of the three species of trout in the Smokies, browns generally prove most difficult to catch.