Rhodeus smithii facts for kids
Quick facts for kids Rhodeus smithii |
|
|---|---|
 |
|
| Conservation status | |
| Scientific classification | |
| Synonyms | |
|
The Japanese rosy bitterling, also called Rhodeus smithii, is a small freshwater fish. It belongs to the carp family and lives in calm waters in Japan. This fish was first described in 1908 by Charles Tate Regan. It is also known as the Japanese bitterling or Nippon baratanago.
This fish was named after Richard Gordon Smith, a British traveler and naturalist. He collected fish specimens in Japan for the British Museum.
The Japanese rosy bitterling is listed as critically endangered on the IUCN Red List. This means it is at very high risk of disappearing forever.
Contents
Meet the Japanese Rosy Bitterling
This fish can grow up to about 6.5 centimeters (2.5 inches) long. It prefers freshwater with a pH level between 6.8 and 7.8. It also likes water temperatures from 10 to 25 degrees Celsius (50 to 77 degrees Fahrenheit).
How They Reproduce
When it's time to lay eggs, the female Japanese rosy bitterling does something special. She places her eggs inside bivalves, like freshwater mussels. The eggs hatch safely inside the mussel. The baby fish stay there until they are big enough to swim on their own.
Lifespan and History
Most Japanese rosy bitterlings live for about three years. They rarely live longer than that. This fish used to be common in western Japan before World War II.
However, in 1942, another type of fish, the rosy bitterling, was brought to Japan by accident. It came with grass carp and silver carp from China. This introduction caused big problems for the native Japanese rosy bitterling.
Comparing Two Similar Fish
The Japanese rosy bitterling and the rosy bitterling look very much alike. But there are some ways to tell them apart. Scientists look at things like the number of scales on their bodies. They also count the rays in their fins.
One easy difference is the color of their fins. The rosy bitterling has a shiny, silvery-white area on its belly fin. The Japanese rosy bitterling, however, has a dark-colored belly fin.
Their size is another clue. The Japanese rosy bitterling usually doesn't grow longer than 6 centimeters (2.3 inches). Rosy bitterling males are often larger than 8 centimeters (3.1 inches). Females of the rosy bitterling commonly grow bigger than 6 centimeters (2.3 inches).
Why the Japanese Rosy Bitterling is in Danger
The Japanese rosy bitterling used to live in many small ponds and creeks in western Japan. But since the rosy bitterling was introduced, its population has grown a lot. These two fish species now live in the same areas. They can also breed with each other very easily.
The Problem of Hybridization
When the two species breed together, they create hybrid fish. This mixing of genes is called hybridization. It has caused the number of pure Japanese rosy bitterlings to drop sharply. Because of this, the fish is now in danger of extinction.
In 1994, the Japanese rosy bitterling was listed as an endangered species. Now, it is considered critically endangered. It is also listed as critically endangered in the Japanese Red Data Book.
Protecting the Japanese Rosy Bitterling
Many things have caused the decline of the native Japanese rosy bitterling. These include pollution and changes to their pond habitats.
Since this fish is critically endangered, many groups in Japan are working to protect it. These include nonprofit organizations and study groups.
Conservation Efforts in Action
One group, the Yao study group, is very active in protecting these fish. For example, in May 1999, they created a special protection pond. They released 41 male and 60 female fish into this pond. They also added freshwater mussels, which the fish need for reproduction.
The group watched the fish and collected data until 2001. In 2000, they successfully increased the fish population to 6,000 individuals. They even moved 500 fish to five other ponds. However, in 2001, they found very few fish. The water quality was poor that year. The group realized that too many nutrients in the water (eutrophication) hurt the fish's reproduction.
Since then, the Yao study group has been working on new ways to clean the water. They also teach children about environmental protection. This helps the next generation learn how to care for these special fish.
