Eel is the general term for species that fall under the classification of the order Eel, also known as eels.
It is a fish with the appearance of a long snake-like body and has the basic characteristics of a fish. In addition, eels are similar to salmon with migratory characteristics. Eels are fish that resemble snakes but have no scales, and are generally found in waters where salt and fresh water meet.
The eel's young is about 6 centimeters long and weighs 0.1 grams, but its head is narrow and its body is high, thin and transparent like a leaf, so it's called "willow leaf fish". Its body fluids are almost the same as those of seawater, so it can be drifted long distances with ocean currents with little effort. It takes about half a year to drift from the spawning grounds back to the Kuroshio current and then back to the coast of Taiwan, and it is only a month before it reaches the shore that it begins to metamorphose into the long, thin, transparent eel threads that are also known as the glassfish.
The eel prefers to live in clean, unpolluted waters.
Eels grow in rivers on land and migrate to spawning grounds in the ocean to lay their eggs when they mature, spawning only once in their lives and dying afterward. This life pattern, in contrast to the anadromous migratory nature of salmon, is called descending migratory. Its life history is divided into six different developmental stages, and in order to adapt to different environments, the body size and body color change greatly from stage to stage.
Egg stage: located in deep-sea spawning grounds. Leaf eel: drifting with the current for long distances in the ocean, at this time the body is flat and transparent, thin as a willow leaf, easy to follow the waves. Glass eel: when approaching coastal waters, the body turns into a streamlined shape to reduce resistance to get out of the strong ocean currents. Eel threads: As they enter estuarine waters, they begin to develop a black pigmentation, but also form a source of capture for eel fry for the aquaculture industry.