Twee River redfin facts for kids
Quick facts for kids Twee River redfin |
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Barbus erubescens |
The Twee River redfin (Sedercypris erubescens) is a special type of ray-finned fish. It belongs to the family called Cyprinidae, which includes many kinds of carp and minnows. This fish was once grouped with other South African redfins. Its closest living relative is the Clanwilliam redfin.
This fish is quite small. It grows to about 40 to 45 millimeters (about 1.5 to 1.7 inches) long when it's ready to have babies. When fully grown, it can be twice that size. During the time they have babies, both male and female fish get bright red fins. This is how they got their name! Male fish, which are usually a bit bigger, also grow small bumps called "nuptial tubercles" on their heads. These bumps are common for fish in the carp family.
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Where the Twee River Redfin Lives
The Twee River redfin lives only in one special place. This place is the Western Cape Province in South Africa. You can find it in the Twee River and some of its smaller rivers. These include the Heks, upper Middeldeur, and upper Suurvlei Rivers. Some redfins have been moved to farm dams. Scientists are still watching to see if they can live well there.
Adult redfins like to live in the deeper parts of rivers. They hide among big rocks or under trees that grow near the water. Young redfins swim together in groups near the water's surface. They often stay close to plants that hang over the water. One important plant for them is called palmiet (Prionium serratum).
What the Twee River Redfin Eats
Twee River redfins mainly eat small creatures that live on the river bottom. These are called benthic invertebrates. Adult fish also eat other things that float by. This can include insects that have fallen into the water.
Twee River Redfin Life Cycle and Reproduction
Twee River redfins have their babies from late spring to early summer. This is usually between October and December. A female fish can lay up to 400 eggs in one season. She lays her eggs in several batches. This means she lays some eggs, then more later, until all her eggs are gone.
Young redfins are ready to have their own babies when they are two years old. These fish can live for up to six years.
Why the Twee River Redfin Needs Help
The Twee River redfin is in big trouble. It is listed as Critically Endangered by the IUCN. This means it is very close to disappearing forever. Since 1987, the number of these fish has dropped a lot. There are only about 4,100 adult redfins left in the world. Also, different groups of redfins can no longer swim to meet each other. This stops them from sharing their genes.
Threats to the Twee River Redfin
The biggest danger to the Twee River redfin comes from other fish. These are fish that eat them or compete for their food.
- Introduced Fish:
- The Cape kurper (Sandelia capensis) is a fish from South Africa. It does not naturally live where the redfin is found. But it was brought into the Suurvlei River. The kurper eats the same food as the redfin. It also probably eats young Twee River redfins. This is likely why redfins disappeared from the lower Suurvlei River.
- The Clanwilliam yellowfish (Labeobarbus capensis) is another South African fish. It was also brought into the redfin's home. It competes with the redfin for food. This has made the number of redfins in the Twee River go down.
- Some foreign fish were also illegally put into the rivers in the 1990s. These include the bluegill (Lepomis macrochirus) and the rainbow trout (Oncorhynchus mykiss). Luckily, these rivers have strong floods and hot summers. This means bluegills and trout do not do very well there.
- Habitat Loss:
- People are also harming the redfin's home. This happens when water gets dirty from water pollution. It also happens when too much water is used.
- Farmers sometimes clear trees and plants near the riverbanks. They do this to plant orchards. This is very bad for the young fish. It takes away their hiding places. It also allows dirty water with pesticides and fertilizers to run into the rivers.
Protecting the Twee River Redfin
The Twee River redfin is also listed as Endangered by the Western Cape Province. It is against the law to kill these fish. For now, they can only be caught if they are being moved to a safer place.
People who own land near the rivers are learning about how special these rivers are. They are also learning about the dangers of farming too close to the riverbanks. Some redfins have been moved to safe areas. Scientists at the University of Johannesburg are also studying how to breed them in tanks.
A plan to save the Twee River redfin is being made. This plan is being developed by CapeNature and the South African Institute of Aquatic Biodiversity.
Images for kids
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Palmiet plants provide shelter for young Twee River redfins.
