Eel vs. fish

Difference Between Eel And fish

 

 

Eel

Eel is the common name for about 400 species of mostly marine snakelike fishes generally inhabiting shallow waters throughout the world. Eels lack pelvic fins. Their dorsal and anal fins are elongate and tend to join with the tail fin to form one continuous “fin” around the body. All but 3 of the 22 marine families are scaleless. One freshwater family of eels has tiny, barely visible scales. Like frogs, freshwater eels have dense networks of blood vessels in their skin and can absorb oxygen directly from air or water.

Snake and Worm Eels

The snake and worm eels are the most highly evolved burrowing forms of eel. They have long, sharply pointed snouts; the pectoral fins are reduced or absent; and the gill apertures are often restricted to very small openings. All lack scales, and many lack caudal fins, possessing instead a sharp-pointed tail for burrowing into sand, mud, or shell hash. The garden eels have large eyes, are extremely slender (about the diameter of a pencil), and are 30 to 50 cm (12 to 20 in) long. They usually live in tropical seas, on sandy slopes from 15 to 60 m (50 to 200 ft) deep that are swept by currents. They remain buried in the sand at night, but during the day they extend 30 to 60 cm (1 to 2 ft) out of their burrows. In this position they sway like blades of grass in the wind, while feeding on small planktonic animals floating by in the water.

When the eels reach about 10 years of age and are black with silvery white underparts, and sufficiently fattened, they cease feeding and begin a seaward journey. Not all mature landlocked eels undergo this migration, but those which do will even cross fields wet with dew to reach seaward rivers. When they reach the sea, both European and American eels head for the Sargasso Sea, a sluggish circle of currents containing much seaweed, situated in the western Atlantic between Bermuda and Puerto Rico. For European eels this journey lasts more than a year. The eels spawn at depths of 400 to 700 m (1,300 to 2,300 ft), each female laying up to several million free-floating eggs. After spawning, the eels die.

Fish

Fish, an aquatic vertebrate (backboned) animal that typically breathes by means of gills and moves by means of fins. Fish are found throughout the world in both fresh and salt water and in widely different habitats. They are cold-blooded animals; that is, their body temperature is usually about the same as the temperature of their environment.

Fish are the most numerous of all vertebrates. There are over 30,000 species of fishes, usually divided into three major groups: the primitive jawless fishes, including lampreys and hagfishes; and two groups of jawed fishes—the cartilaginous fishes, including sharks, skates, and rays, and the bony fishes, which are by far the largest group and include most of the familiar fishes such as trout, perch, bass, cod, halibut, and tropical fishes raised in home aquaria. The so-called shellfish, of course, are not fish at all; these invertebrate animals are either crustaceans (such as shrimp, lobsters) or mollusks (such as clams, oysters).

 

 

 

Eel

Eel is the common name for about 400 species of mostly marine snakelike fishes generally inhabiting shallow waters throughout the world. Eels lack pelvic fins. Their dorsal and anal fins are elongate and tend to join with the tail fin to form one continuous “fin” around the body. All but 3 of the 22 marine families are scaleless. One freshwater family of eels has tiny, barely visible scales. Like frogs, freshwater eels have dense networks of blood vessels in their skin and can absorb oxygen directly from air or water.

Snake and Worm Eels

The snake and worm eels are the most highly evolved burrowing forms of eel. They have long, sharply pointed snouts; the pectoral fins are reduced or absent; and the gill apertures are often restricted to very small openings. All lack scales, and many lack caudal fins, possessing instead a sharp-pointed tail for burrowing into sand, mud, or shell hash. The garden eels have large eyes, are extremely slender (about the diameter of a pencil), and are 30 to 50 cm (12 to 20 in) long. They usually live in tropical seas, on sandy slopes from 15 to 60 m (50 to 200 ft) deep that are swept by currents. They remain buried in the sand at night, but during the day they extend 30 to 60 cm (1 to 2 ft) out of their burrows. In this position they sway like blades of grass in the wind, while feeding on small planktonic animals floating by in the water.

When the eels reach about 10 years of age and are black with silvery white underparts, and sufficiently fattened, they cease feeding and begin a seaward journey. Not all mature landlocked eels undergo this migration, but those which do will even cross fields wet with dew to reach seaward rivers. When they reach the sea, both European and American eels head for the Sargasso Sea, a sluggish circle of currents containing much seaweed, situated in the western Atlantic between Bermuda and Puerto Rico. For European eels this journey lasts more than a year. The eels spawn at depths of 400 to 700 m (1,300 to 2,300 ft), each female laying up to several million free-floating eggs. After spawning, the eels die.

Fish

Fish, an aquatic vertebrate (backboned) animal that typically breathes by means of gills and moves by means of fins. Fish are found throughout the world in both fresh and salt water and in widely different habitats. They are cold-blooded animals; that is, their body temperature is usually about the same as the temperature of their environment.

Fish are the most numerous of all vertebrates. There are over 30,000 species of fishes, usually divided into three major groups: the primitive jawless fishes, including lampreys and hagfishes; and two groups of jawed fishes—the cartilaginous fishes, including sharks, skates, and rays, and the bony fishes, which are by far the largest group and include most of the familiar fishes such as trout, perch, bass, cod, halibut, and tropical fishes raised in home aquaria. The so-called shellfish, of course, are not fish at all; these invertebrate animals are either crustaceans (such as shrimp, lobsters) or mollusks (such as clams, oysters).

 

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