Spring Cavefish

Originally found in a deep well in Lebanon, Tennessee, the spring cavefish is distributed within the central and southeastern United States. It inhabits select springs, spring runs/seeps, and caves from central and western Kentucky, west towards the Tennessee River, to south central Tennessee. It also is located in areas west across southern Illinois to southeastern Missouri. The spring cavefish's distribution has decreased from within its original streams and springs. This species is affected by the activities on the surface of the ground. Any activity that reduces water quality or quantity affects the spring cavefish. It is vulnerable to pollution from many different sources. Some of these sources include nearby agricultural fields, pastures, septic tanks, sewage lagoons, urban runoff, mines, and livestock waste. Some of the springs fluctuate drastically in flow and turbidity as a result of direct connections with surface drainage or they were enclosed as water supplies or otherwise modified by man.

Spring cavefish stay underground after dawn, but then emerge into surface waters at dusk. They are dark brown dorsally and fade to a creamy brown towards the pelvis and reach a maximum length of 3.5 in (8.9 cm). The head is sloped, and it has a protruding lower jaw. The fish has no pelvic fin or adipose fin. Its dorsal fin is set further back compared to most fish. This species is susceptible to developing retinoblastomas. The spring cavefish is well adapted to its environment, as it has a well-developed sensory system. This system occurs in clusters on the head. Most fish detect food by sight, taste, touch, or smell, or by a combination of these senses. Sight is important in the detection of food by most species, but this is presumably excluded with the slightly blind spring cavefish. They use their underdeveloped eyes to distinguish between light and darkness. However, spring cavefish cannot readily distinguish between edible and inedible substances by touch alone, but once in contact with the lips, the sense of taste enables the fish to distinguish among these items. Another hurdle for this species is food is often lacking in their habitats, so they compensate for this scarcity of food with cannibalistic behavior. …

The breeding behavior of spring cavefish is sparsely documented. Spawning occurs underground and in darkness between January and April. Spring cavefish are oviparous; however, the eggs are carried in gill chambers of the females. Females produce roughly 100 young per female. The average spring cavefish lives for about three years and typically reaches a length of about 1.8 to 2.6 inches (4.6 to 6.6 cm).