Sladen's hatchetfish facts for kids
Quick facts for kids Sladen's hatchetfish |
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| Conservation status | |
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| Genus: |
Argyropelecus
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| Species: |
sladeni
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The Sladen's hatchetfish, also known by its scientific name Argyropelecus sladeni, is a type of fish. It belongs to a group called ray-finned fish, which means its fins are supported by bony rays. This small fish is part of the Sternoptychidae family, known for their unusual, hatchet-like bodies. You can find these fish in the warm, tropical, and subtropical parts of the Atlantic, Indian, and Pacific Oceans.
During the day, Sladen's hatchetfish live deep in the ocean in a place called the mesopelagic zone. This is sometimes called the "twilight zone" because only a little sunlight reaches it. But at night, these fish swim up closer to the surface. This daily journey is called a daily vertical migration. They move into the epipelagic zone, which is the sunlit top layer of the ocean.
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What's in a Name?
This interesting fish was named after a British scientist named Percy Sladen. He studied sea creatures like starfish and sea urchins. The fish's name also honors the Percy Sladen Memorial Trust. This group helped pay for an important trip to the Indian Ocean where this type of fish was first found.
What Does Sladen's Hatchetfish Look Like?
Sladen's hatchetfish is a small fish, usually growing up to about 60 millimeters (about 2.4 inches) long. It has a deep body, which means it's tall from top to bottom but not very long. It also has a special keel, or ridge, on its belly.
- Its mouth is a medium size.
- Its eyes are like tubes and point upwards, helping it see what's above.
- The fin on its back, called the dorsal fin, has nine soft rays.
- It also has a small, fatty fin on its back called an adipose dorsal fin.
- The fins on its sides, called pectoral fins, have 10 to 11 soft rays.
- The fins on its underside, called pelvic fins, have 6 rays.
- The fin near its tail, called the anal fin, is split into two parts.
- It has special bony spines near its gills and on its belly.
- The top of the fish is dark, but its sides are shiny and silver.
- It has photophores, which are special light-producing spots. These are found on its gill cover (called the operculum) and on its belly. These lights help it hide from predators by matching the dim light from above.
Where Do These Fish Live?
Sladen's hatchetfish can be found all over the world in tropical and subtropical oceans. They are truly global travelers!
As we learned, these fish make daily trips up and down in the water.
- During the day, they usually live between 350 to 600 meters (about 1,150 to 1,970 feet) deep.
- At night, they swim up to shallower waters, from 100 to 375 meters (about 330 to 1,230 feet) deep.
Scientists often use special nets called trawls to catch and study these fish. They find the most hatchetfish between 300 and 400 meters (about 980 to 1,300 feet) deep during the day. At night, the largest numbers are found closer to the surface, between 0 and 200 meters (about 0 to 660 feet) deep.
What Do Sladen's Hatchetfish Eat?
Sladen's hatchetfish are not picky eaters! They feed on tiny living things that float in the water, which are called plankton. Their diet includes:
- Small shrimp-like creatures called krill.
- Tiny crustaceans called amphipods.
- Even smaller crustaceans called copepods.
- And other tiny shelled creatures known as ostracods.
Reproduction and Life Cycle
Sladen's hatchetfish reproduce by laying eggs. This is called being oviparous. Both their eggs and their newly hatched babies (larvae) float around in the ocean as part of the plankton. They drift with the currents until they grow big enough to swim on their own.
Conservation Status
Good news for Sladen's hatchetfish! This fish is very common and found in large numbers across its wide ocean home. There are no known big threats to this species. Because of this, the International Union for Conservation of Nature has listed its conservation status as "least concern". This means scientists are not worried about it becoming endangered anytime soon.
