Orangefin darter facts for kids

Quick facts for kids Orangefin darter
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Perciformes
Family:	Percidae
Genus:	Etheostoma
Species:	E. bellum
Binomial name
Etheostoma bellum Zorach, 1968
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The orangefin darter (Etheostoma bellum) is a cool freshwater fish. It's a type of darter, which belongs to the same fish family as perches. You can find this fish in the Barren River and Green River systems. These rivers flow through parts of Tennessee and Kentucky.

This fish is medium-sized and grows up pretty fast, usually becoming an adult between one and two years old. Male orangefin darters are very protective of their space. They lay their eggs in the gravel of fast-moving parts of the river, usually from late April to late June. Both young and adult orangefin darters are skilled hunters. They mostly eat tiny insect larvae.

Where Orangefin Darters Live

Orangefin darters are only found in the Green River and Barren River areas. The Green River is the bigger of the two. The Barren River flows into the Green River. This area is known as a "biodiversity hotspot." This means it has a huge variety of living things.

The hotspot is a 100-mile stretch of the Green River. It goes from the Green River reservoir dam to Mammoth Cave National Park. Over 150 kinds of fish and 70 types of mussels live here. Many other water animals also call this place home.

The Green River flows into the Mississippi River. However, orangefin darters do not travel that far down the river system. The Green River is always flowing. It has many waterfalls and mountain springs. These keep the water clean and give it a deep, green look.

The Barren River starts in Tennessee but mostly flows through Kentucky. It is north of the Nashville Basin. It drains parts of Clay, Macon, and Sumner Counties. The Barren River joins the Green River near Warren County, Kentucky. These rivers are usually cool and clear. They have gravel bottoms and areas with fast-moving water and calm pools.

How Orangefin Darters Live and Interact

Scientists studied the upper Green River system. They looked at six types of darters that live only there. They checked over 300 spots for 13 years. They looked at areas like farms, forests, water, and developed land.

Orangefin darters were found in almost half of the places studied. They live in all the main river systems in the area. This darter was seen more often than the other five darter species. They were usually found in areas with lots of forest cover. They also liked areas below large dams.

These darters prefer fine, loamy soils with good water flow. The water temperature is usually around 50 degrees Fahrenheit (10 degrees Celsius). Orangefin darters need the right environment to eat and lay eggs. But in these areas, they also face predators and competition.

Larger freshwater fish hunt darters. These include fish like catfish and smallmouth bass. Orangefin darters also compete with each other for food. Small water insects are more common at certain times of the year. Finding good breeding spots can also be a challenge. Darters sometimes eat small fish larvae, which adds to the competition.

Competition between different species can happen too. This might be due to many predators. Human activities can also cause problems. More farming, cutting down forests, or pollution can reduce the number of darters. Building dams can slow down the water flow. This greatly affects orangefin darters. They need rocky areas and fast-moving water to hide and find food. Their home must stay balanced. If not, these special fish could become extinct.

Reproduction and Life Cycle

The orangefin darter is a medium-sized fish. It lives only in the Green and Barren River systems. These are in south-central Kentucky and north-central Tennessee. They lay their eggs from late April to late June. They do this in fast-flowing parts of the river with gravel bottoms.

Darters usually stay in deeper water. But when it's time to lay eggs, they become more active. They move to areas with better water flow, rocks, and fast-moving sections. When breeding begins, the male darters are very territorial. The larger, mature males attract the females to lay eggs.

The male's bright colors are very important for breeding. Females prefer males with certain colors from their own species. When a female chooses a male, she buries herself in the gravel in his territory. They lay groups of eggs, usually 60 to 100 at a time. Only some of these eggs will hatch. They hatch in about 7 to 9 days in water that is about 23 degrees Celsius (73 degrees Fahrenheit).

The male guards the nest for a few days. But then he leaves, and the hatched eggs are on their own. Orangefin darters become adults in one to two years. Males seem to mature faster. Their lifespan is about five years.

Their diet mostly includes tiny water mites, mayfly nymphs, and fly larvae. What they eat can change a bit depending on the time of year. They eat the most in the afternoon. Young and adult darters mostly eat the same kinds of food. Young darters usually stay in shallow waters for a while. Adults go back to deeper waters after breeding.

Naming the Orangefin Darter

The orangefin darter was first officially described in 1968. This was done by a scientist named Timothy Zorach. He found the first known specimen in White Oak Creek, Tennessee. Zorach first put this fish in a group called Nothonotus. However, the Fishbase website now classifies it within the larger group Etheostoma.

Protecting the Orangefin Darter

Even though the orangefin darter lives in a small area, it is not considered endangered. The IUCN (International Union for Conservation of Nature) lists it as "least concern." This is because there are many groups of these fish. Their population size is large, and it seems to be stable. Also, there are no major threats to them right now.

The Nature Conservancy is a group that works to protect nature. They have a conservation project in the Green River. This river is home to the orangefin darter. Their work helps keep the darter's habitat healthy.