Ghost Fish of the Ozarks
Mystery and imagination take over when we think about caves. These dark places harbor magical creatures. In fact, stories of "ghost fish" living in caves have been told since the days Native Americans roamed the Missouri Ozarks.
That "ghost fish" today is known as the Ozark cavefish. It is a 2-inch long, pale, almost colorless blind fish living only in caves and springs on the Springfield Plateau of southwest Missouri and nearby parts of Oklahoma and Arkansas.
Ruth Hoppin, a caver and explorer, collected cavefish in Jasper County in 1888. She also collected the first specimens of the bristly cave crayfish, an unpigmented, blind crayfish that has a range similar to the Ozark cavefish.
Like many other cave-adapted animals, Ozark cavefish have lost their skin pigmentation, leaving them so translucent that their blood vessels are visible. Eyes are unnecessary for creatures living in near perpetual darkness, so they have gradually devolved to become small spots of residual nerves. Although cavefish do not have eyes, they "see" with sensory organs on their head and sides. These small whiskerlike projections help the fish feel its way through the water and detect the movements of prey.
Because the nutrient supply is limited in a cave, Ozark cavefish are not picky about what they eat. Cavefish eat bacteria, fungi, protozoans and aquatic insect larvae, as well as mites that feed on decaying organisms brought into the cave by animals. Their diet also includes plankton (microscopic plants and animals) and small invertebrates, such as crayfish, cave crickets, salamander larvae, amphipods and isopods. If food is really hard to find, they may even eat their own young.
Because caves have relatively constant temperatures and stable dissolved oxygen levels, cavefish have evolved low metabolic rates and do not require much food. Regardless, life in a cave is life "on the edge."
When the early settlers dipped drinking water out of the well, they sometimes found cavefish in their bucket. The custom of calling them "spring keepers" or "well keepers" sprang from these encounters. People saw them as a good luck charm and believed that the cavefish meant the water was safe to drink-a belief that continues today.
Clifford Lewis, a landowner near Sarcoxie in southwest Missouri, remembers seeing cavefish when he was a boy. "My brother and I were mowing hay on a hot summer day. When we got thirsty, we headed to the nearby cave to quench our thirst with spring water. Those blind