Amphibious fish
Encyclopedia
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
that are able to leave water for extended periods of time. About 11 distantly related genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of fish are considered amphibious. This suggests that many fish genera independently evolve
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
d amphibious traits. These fish use a range of terrestrial locomotory mode
Mode
Mode may mean:* Transport mode, a means of transportation* Block cipher modes of operation, in cryptography* A technocomplex of stone tools...
s, such as lateral undulation, tripod
Tripod
A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. The word comes from the Greek tripous, meaning "three feet". A tripod provides stability against downward forces, horizontal forces and moments about the...
-like walking (using paired fin
Fin
A fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media, . The first use of the word was for the limbs of fish, but has been extended to include other animal limbs and man-made devices...
s and tail
Tail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
), and jumping. Many of these locomotory modes incorporate multiple combinations of pectoral, pelvic and tail fin movement.
Many ancient fish had lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
-like organ
Organ (anatomy)
In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...
s, and a few, such as the lungfish
Lungfish
Lungfish are freshwater fish belonging to the Subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed...
, still do. Some of these ancient "lunged" fish were the ancestor
Ancestor
An ancestor is a parent or the parent of an ancestor ....
s of tetrapod
Tetrapod
Tetrapods are vertebrate animals having four limbs. Amphibians, reptiles, birds and mammals are all tetrapods; even snakes and other limbless reptiles and amphibians are tetrapods by descent. The earliest tetrapods evolved from the lobe-finned fishes in the Devonian...
s. However, in most recent fish species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
these organs evolved into the swim bladders, which help control buoyancy
Buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...
. Having no lung-like organs, modern amphibious fish and also many fish in oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
-poor water use other methods such as their gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
s or their skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
to breathe air. Amphibious fish may also have eyes adapted to allow them to see clearly in air, despite the density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
differences between air and water.
Lung breathers
- Various "lunged" fish: These are now extinct. A few of this group were ancestors of the basal tetrapods that led to all tetrapods: amphibians, reptiles, birds, and mammals.
- LungfishLungfishLungfish are freshwater fish belonging to the Subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed...
(Dipnoi): Six species, have limbLimb (anatomy)A limb is a jointed, or prehensile , appendage of the human or other animal body....
like fins, and can breathe air. Some are obligate air breathers. Some species will bury in the mud when the body of water they live in dries up, surviving up to two years until water returns.
Gill or skin breathers
- Rockskippers: These blennies are found in PanamaPanamaPanama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
and elsewhere on the western coastline of the Americas. These fish come onto land to catch prey and escape aquatic predators. They often come out of water for up to 20 minutes. Leaping blennies (Alticus arnoldorumAlticus arnoldorumAlticus arnoldorum is a species of combtooth blenny found at reefs in the tropical west and south Pacific. It is commonly known as the Pacific leaping blenny or the leaping rockskipper....
) are able to jump over land using their tails http://www.wired.com/wiredscience/2010/06/leaping-blennies/. - Wooly sculpin: Found in tide pools along the Pacific coastPacific CoastA country's Pacific coast is the part of its coast bordering the Pacific Ocean.-The Americas:Countries on the western side of the Americas have a Pacific coast as their western border.* Geography of Canada* Geography of Chile* Geography of Colombia...
, these sculpinSculpinA Sculpin is a fish that belongs to the order Scorpaeniformes, suborder Cottoidei and superfamily Cottoidea, that contains 11 families, 149 genera, and 756 species...
s will leave water if the oxygen levels get low and can breathe air for 24 hours. - MudskipperMudskipperMudskippers are members of the subfamily Oxudercinae , within the family Gobiidae . They are completely amphibious fish, fish that can use their pectoral fins to walk on land...
s (Oxudercinae): This subfamily of gobies is probably the most land adapted of fish. Mudskippers are found in mangrove swamps in AfricaAfricaAfrica is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
and the Indo-PacificIndo-PacificThe Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
, they frequently come onto land and can survive in air for up to three and a half days. Mudskippers breathe through their skin and also through the lining of the mouth (the mucosa) and throat (the pharynxPharynxThe human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
). This requires the mudskipper to be wet, limiting mudskippers to humid habitats. This mode of breathing, similar to that employed by amphibians, is known as cutaneous breathing. They propel themselves over land on their sturdy forefins. - EelEelEels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...
s: Some eels, such as the European eelEuropean eelThe European eel, Anguilla anguilla, is a species of eel, a snake-like, catadromous fish. They can reach in exceptional cases a length of 1½ m, but are normally much smaller, about 60–80 cm, and rarely more than 1 m....
and the American eelAmerican eelThe American eel, Anguilla rostrata, is a catadromous fish found on the eastern coast of North America. It has a snake-like body with a small sharp pointed head. It is brown on top and a tan-yellow color on the bottom. It has sharp pointed teeth but no pelvic fins...
, can live for an extended time out of water and can crawl on land if the soil is moist. - Snakehead fish (ChannidaeChannidaeThe Snakeheads are members of the freshwater perciform fish family Channidae, native to Africa and Asia. These elongated predatory fish are distinguished by a long dorsal fin, large mouth and shiny teeth. They breathe air with a suprabranchial organ, a primitive form of a labyrinth organ...
): This family of fish are obligate air breathers, breathing air using their suprabranchial organ, which is a primitive labyrinth organ. The Northern SnakeheadNorthern snakeheadThe Northern snakehead is a type of snakehead fish native to China, Russia, North Korea and South Korea. In the United States, the fish is considered to be a highly invasive species...
of Southeast AsiaSoutheast AsiaSoutheast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
can "walk" on land by wriggling and using its pectoral fins, which allows it to move between the slow-moving, and often stagnant and temporary bodies of water in which it lives. Another amphibious species of this family is the Eel catfishEel catfishThe eel catfish, Channallabes apus, is an airbreathing catfish found in the muddy swamps of the tropics of western Africa. The fish is 30 - 40 cm long and is notable for the ability to propel itself out of the water to catch prey. This species was formerly thought to be the sole member of its genus...
(Channallabes apus), which lives in swamps in Africa, and known to hunt beetles on land. - Labyrinth fish (AnabantoideiAnabantoideiThe Anabantoidei is a suborder of perciform ray-finned freshwater fish distinguished by their possession of a lung-like labyrinth organ, which enables them to breathe air. The fish in the Anabantoidei suborder are known as anabantoids or labyrinth fish...
). This suborder of fish also use a labyrinth organ to breathe air. Some species from this group can move on land. An amphibious fish from this family is the Climbing gouramiClimbing gouramiThe Anabantidae are a family of perciform fish commonly called the climbing gouramies or climbing perches. As labyrinth fishes, they possess a labyrinth organ, a structure in the fish's head which allows them to breathe atmospheric oxygen...
, an African and Southeast Asian fish that is capable of moving from pool to pool over land by using its pectoral fins, caudal peduncle and gill covers as a means of locomotion. It is said that climbing gourami move at night in groups. - Electric eelElectric eelThe electric eel , is an electric fish, and the only species of the genus Electrophorus. It is capable of generating powerful electric shocks, of up to six hundred volts, which it uses for both hunting and self-defense. It is an apex predator in its South American range...
. The electric eel is an obligate air-breather.