Dark-edged splitfin facts for kids
Quick facts for kids Dark-edged splitfin |
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The dark-edged splitfin (Girardinichthys multiradiatus) is a special type of fish that lives only in Mexico. It's a cold-water fish found in the mountains. This fish is unique because it gives birth to live young, unlike many fish that lay eggs. It's also very sensitive to water temperature. If the water is too cold, all the baby fish will be male. If it's too hot, females might have only a few babies and then die. This makes it hard for them to survive and grow their numbers. The dark-edged splitfin mainly eats insects. Sadly, this fish is an endangered species, meaning its population is at risk.
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What Does the Dark-Edged Splitfin Look Like?
The dark-edged splitfin fish comes in different shades of yellow, from a dull grey-yellow to a bright, sunny yellow. Female splitfins can grow to about 3 inches long. Males are a bit smaller, reaching about 2.5 inches.
Fins and Features
This fish is sometimes called the "golden sailfin goodeid." This is because of their long, flowing fins, especially on the males. Male splitfins have a special notch in their anal fin (the fin on their belly). Their dorsal (top) and anal fins are also longer and wider than those of the females.
Female splitfins usually have clear fins. Male fins are yellow with a black band at the end. Females also have clear stripes near the back of their bodies.
Where Does the Dark-Edged Splitfin Live?
You can find the dark-edged splitfin in Mexico. They prefer water that is still or moves very slowly. Their homes are usually small lakes, ponds fed by springs, or pools next to colder streams.
Water Conditions
These fish like water that can be clear or a bit muddy. The bottom of their habitat might be made of silt, mud, clay, sand, gravel, or rocks. They also prefer water that is less than 1 meter (about 3 feet) deep. Their homes often have lots of green algae.
The water they live in usually has a pH between 7 and 9. This means it's slightly neutral to a bit alkaline. The amount of oxygen in the water is usually between 7 and 10 parts per million (ppm). They like water temperatures that are between 20–25 degrees Celsius (68–77°F) when it's warm. When it's cooler, they prefer temperatures between 10–18 degrees Celsius (50–64°F).
How Do Dark-Edged Splitfins Behave?
Social Life of the Splitfin
Dark-edged splitfins tend to swim together in groups, which is called schooling. They have a special way to sense what's happening around them. It's called their lateral line system. This system helps them feel movements in the water. They use it to school together, swim against currents, and even know when a predator is nearby. They also use water movements to show how they feel to other fish.
What Do They Eat?
Dark-edged splitfin fish are mostly carnivores, meaning they eat meat. They feed on many different kinds of insects. Studies have shown that their stomachs often contain larvae of midges (chironomid-larvae), mayflies, and other small insects like Hymenoptera and Diptera-larvae. They also eat tiny crustaceans called Cladocera. Young splitfins, called juveniles, mostly eat Cladocera and Diptera.
How Do They Have Babies?
Dark-edged splitfins usually breed between March and September. This is when the water temperatures start to get warmer. The mother fish carries her babies for about 55 days. After this time, she gives birth to live young. A female can have anywhere from 10 to 20 baby fish, called fry, in one group. It seems that female splitfins choose who they want to mate with based on how the male performs his courtship dance.
Courtship Dance
The way a male splitfin courts a female is something they can inherit. It's also influenced by the females they grow up with. When a male approaches another fish, he shows off his fins and stays still. He might face the other fish directly or show his side fins.
If the other fish is a male, it will also show its fins and stay still. This often leads to a small fight between the two males. If the other fish is a female, she will fold her fins and vibrate her body. The male will then stop his still pose and start his courtship dance to attract her. This dance involves waving his fins and shaking his body in a figure-eight motion. Females can react in many ways, like showing their own fin displays, swimming away, approaching the male, or even trying to nip him.
History of the Dark-Edged Splitfin's Name
The first dark-edged splitfin was found in the early 1900s. Scientists have changed its name a few times over the years. It was first called Girardinichthys innominatus. Later, it was moved to a new group called Lermichthys. Then, it got a new description as Girardinichthys limnurgus. Finally, in 1971, scientists decided its current name, Girardinichthys multiradiatus, was the best fit.
Why Is the Dark-Edged Splitfin Endangered?
The Girardinichthys multiradiatus is an endangered species. This means its population is shrinking, and it's at risk of disappearing forever.
Dangers They Face
Many things threaten the dark-edged splitfin. Pollution from cities, factories, farms, and animal waste harms their water homes. Other types of fish that are not native to Mexico are also a big problem. These non-native fish are aggressive and eat the baby splitfins. They also compete with the splitfins for food, making it harder for them to find enough to eat.
Helping the Splitfin Survive
There are groups working to protect the dark-edged splitfin. The Lakes of Zempoala National Park and the University of Michoacan are helping. They work on protecting the land and water where the fish live. This includes protecting their habitats and managing resources. They also work to control invasive species that threaten the splitfins. Plus, they try to educate people and raise awareness about the importance of protecting this unique fish.
