Tennessee dace facts for kids

Quick facts for kids Tennessee dace
Conservation status
Vulnerable (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Leuciscidae
Subfamily:	Laviniinae
Genus:	Chrosomus
Species:	C. tennesseensis
Binomial name
Chrosomus tennesseensis (W. C. Starnes & R. E. Jenkins, 1988)
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Synonyms
Phoxinus tennesseensis Starnes & Jenkins, 1988

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The Tennessee dace (Chrosomus tennesseensis) is a small, colorful ray-finned fish from the Cyprinidae family, which includes minnows and carps. It lives only in the United States, mainly in northeast Tennessee, southwest Virginia, and parts of northwest Georgia. For a long time, people thought it was just a type of mountain redbelly dace. You can often find these fish in small, spring-fed streams in East Tennessee. They like quiet spots with fine gravel or under banks where the water doesn't flow too fast. These streams are usually less than two meters wide.

Like other Tennessee dace, this fish has very tiny scales and a scaled chest. They often have bright red bellies, making them one of the prettiest native fish in Tennessee.

Tennessee dace are special because they use the nests of other fish, like central stonerollers and common creek chubs, to lay their eggs. There's even a chance they can breed with common creek chubs. They lay their eggs from April to July. Both male and female dace get even brighter colors during this breeding time.

These fish eat mostly algae that grows on rocks. Sadly, because there aren't many places where they live, and for other reasons, they are considered "in need of management" in Tennessee. Things like human buildings and climate change could threaten them in the future.

What Makes the Tennessee Dace Special?

The Tennessee dace (Chrosomus tennesseensis) is part of a group of fish that includes the mountain blackside dace, mountain redbelly dace, and laurel dace. Until recently, many thought the Tennessee dace was just a different kind of mountain redbelly dace. But scientists found some key differences.

The Tennessee dace has a broken dark stripe along its side. Also, the dark spots above this stripe are smaller than the fish's eye pupil. The mountain redbelly dace, on the other hand, has spots that are larger than its pupil. The mountain redbelly dace is also a bit stronger-looking and has fewer scales. The name "tennesseensis" means "from Tennessee," which is where most of these fish live.

Appearance of the Tennessee Dace

The Tennessee dace has a complete lateral line, which is a sensory organ that helps fish detect movement in the water. Their back can be plain olive green or have many black speckles. During breeding season, male dace become very colorful. Their lower sides and bellies turn bright red. Red spots also appear around their gill covers, near their eyes, and at the base of their dorsal fin.

Their pectoral, pelvic, and anal fins are yellow. Their chest and lower head turn black. Bright silver patches can be seen at the front base of their dorsal, pectoral, and pelvic fins. Male and female Tennessee dace look different from each other. Males have more rounded pectoral fins, while females have narrower and pointier fins.

Where the Tennessee Dace Lives

The Tennessee dace lives in a very small area. You can only find it in eastern Tennessee, the very southwest part of Virginia, and northwest Georgia. As of 2008, scientists knew of only 62 places where these fish live.

They are found in small streams in the ridge and valley areas of the Blue Ridge and Cumberland Plateau regions. These areas are part of the upper Tennessee River system. They live in places like the Emory and lower Clinch river systems, and south to the Hiwassee River system. They probably used to live in Whiteside, west of Chattanooga, but are likely gone from there now.

Tennessee Dace Habitat and Diet

Tennessee dace live in small streams that are fed by springs. These streams are usually less than two meters wide and are often shaded by trees and plants like hemlock and rhododendron. They prefer areas with limestone rocks. In the streams, they like quiet pools with silt and fine gravel. They also hide under banks with woody debris, like fallen branches and roots.

Studies show that these root masses and woody plants are very important for the dace to survive. Adult fish use the roots for cover, and young dace are often found hiding inside them. Any debris that falls into the stream also gives them extra places to hide.

Like other dace species, Tennessee dace eat algae that they scrape off rocks and other things on the stream bottom. When they eat algae, they also accidentally swallow tiny sand particles. These sand grains help them digest their food by breaking open the tough cell walls of the plants. They might also get food from root hairs and bacteria that live with the algae. In winter, when algae is scarce, they eat small insects. Most of their insect diet comes from Dipteran (fly) and caddis fly larvae.

Not much is known about what animals eat Tennessee dace. But it's known that mammals and birds sometimes catch them in shallow parts of the streams.

Reproduction and Life Cycle

Tennessee dace lay their eggs from April to July. They have been seen spawning when the water temperature is around 21°C (70°F). They can lay eggs twice during this period, but most only do it once in their lives. Like other Chrosomus fish, they usually lay eggs in the afternoon on clear days.

Female Tennessee dace don't produce as many eggs as some similar fish. They lay between 398 and 721 eggs. For example, mountain blackside dace can lay nearly 3,000 eggs.

Scientists have seen many male Tennessee dace following a single female through pools. Sometimes as many as 20 males follow one female in a straight line, with each male's nose just behind the tail of the one in front. They have also been seen jumping out of the water about an hour before and after laying eggs.

Tennessee dace are "nest associate spawners." This means they use nests already built by other fish to lay their eggs. They use the nests of common creek chubs and central stonerollers. If no nests are available, some Chrosomus species might use shallow, rocky areas in streams. Using another fish's nest has benefits, like the nest providing physical protection and the host fish protecting the eggs. However, this behavior might also be why some of these fish are rare. Several minnow species that use other fish's nests are protected by law. Tennessee dace start laying eggs as soon as the fish that built the nest leaves it. Scientists think that a chemical signal from the nest-building fish might tell the dace when to start spawning.

Sometimes, different types of minnows in North America breed together, and this can happen with the Tennessee dace and the common creek chub. This likely happens because they both use gravel nests to breed. When streams become polluted or damaged, it can make it harder for fish to find clean gravel for nests. This might increase the chances of different species breeding together.

Protecting the Tennessee Dace

The Tennessee dace is listed as "G3," which means it's globally vulnerable to disappearing. It's also listed as "S3," meaning it's vulnerable to disappearing or becoming extinct in its state. In Tennessee, it's considered "in need of management," and in Virginia, it's listed as "endangered." This means people are working to protect this special fish and its habitat.