black sculpin

Dromus dromas, the dromedary pearlymussel or dromedary naiad, is a rare species of freshwater mussel in the family Unionidae. This aquatic bivalve mollusk is native to the Cumberland and Tennessee River systems in the United States, where it has experienced a large population decline. It is a federally listed endangered species of the United States.
This mussel is yellow-green in color with interrupted green rays on the shell. The nacre is white, pink, or reddish. The species got its name from the distinctive hump on the shell of larger individuals. A "headwaters form," D. dromas form caperatus (Lea, 1845) has additionally been described.
This species lives in clear, clean, fast-flowing water. It cannot tolerate water of poor quality, for example, water with silt.
Like other freshwater mussels, this species reproduces by releasing larvae called glochidia into the water. The glochidia are eaten by fish and lodge in the fish's gills, where they develop into juvenile mussels. Fish hosts for this mussel species include black sculpin (Cottus baileyi), greenside darter (Etheostoma blennioides), fantail darter (Etheostoma flabellare), snubnose darter (Etheostoma simoterum), tangerine darter...