Sharks are a group of fish characterized by a cartilaginous skeleton. five to seven gill slits on the sides of the caput. andpectoral fives that are non fused to the caput. Modern sharks are classified within the clade Selachimorpha ( or Selachii ) and are the sister group to the beams. However. the term “shark” has besides been used for nonextant members of the subclassElasmobranchii outside the Selachimorpha. such as Cladoselache and Xenacanthus. Under this broader definition. the earliest known sharks day of the month from more than 420 million old ages ago.
Since so. sharks have diversified into over 470 species. They range in size from the little midget lanternshark ( Etmopterus perryi ) . a deep sea species of merely 17 centimeters ( 6. 7 in ) in length. to the giant shark ( Rhincodon typus ) . the largest fish in the universe. which reaches about 12 meters ( 39 foot ) . Sharks are found in all seas and are common to deepnesss of 2. 000 meters ( 6. 600 foot ) . They by and large do non populate in fresh water although there are a few known exclusions. such as the bull shark and the river shark. which can last in both saltwater and freshwater. ] They breathe through five to seven gill slits. Sharks have a covering of cuticular denticles that protects their tegument from harm and parasites in add-on to bettering their fluid kineticss. They have several sets of replaceable dentitions. Well-known species such as the great white shark. tiger shark. bluish shark. mako shark. and the dunce shark areapex predators—organisms at the top of their submerged nutrient concatenation
Tetraodontidae is a household of chiefly Marine and estuarial fish of the order Tetraodontiformes. The household includes many familiar species. which are diversely called blowfish. blowfishs. Diodon holocanthus. sea squab. bubblefish. globefish. swellfish. toadfish. sycophants. honey frogs. sugar frogs. and sea dove. [ 1 ] They are morphologically similar to the closely relatedporcupinefish. which have big external spinal columns ( unlike the dilutant. concealed spinal columns of Tetraodontidae. which are merely seeable when the fish has puffed up ) . The scientific name refers to the four big dentitions. fused into an upper and lower home base. which are used for oppressing the shells of crustaceans and molluscs. their natural quarry.
Blowfish are by and large believed to be the second-most toxicant craniates in the universe. after the aureate toxicant toad. Certain internal variety meats. such as liver. and sometimes the tegument. contain tetrodotoxin and are extremely toxic to most animate beings when eaten ; however. the meat of some species is considered a daintiness in Japan ( as ?? . pronounced as fugu ) . Korea ( as ?bok or ?? bogeo ) . and China ( as ?? hetun ) when prepared by specifically trained chefs who know which portion is safe to eat and in what measure. The Tetraodontidae contain at least 120 species of blowfishs in 19 genera. [ 1 ] They are most diverse in the Torrid Zones. comparatively uncommon in the temperate zone. and wholly absent from cold Waterss. They are typically little to medium in size. although a few species can make lengths of greater than 100 centimeter ( 39 in ) .
The Eden fish. paradisefish. or paradise gourami. Macropodus opercularis. is a species of gourami found in most types of fresh H2O in East Asia. runing from the Korean Peninsula to northern Vietnam. This species can make a length of 6. 7 centimeter ( 2. 6 in ) . though most are merely approximately 5. 5 centimeter ( 2. 2 in ) . Paradise gouramis were one of the first cosmetic fish available to western fish tank keepers. holding been imported toEurope every bit early as the nineteenth century. The Eden fish is one of the more aggressive members of its household. It is more aggressive than the three topographic point gourami. yet less hard-bitten in nature than the less commonly kept combtail.
Paradise fish are reasonably contentious. harassing and assailing each other. every bit good as potentially killing little fish. In the natural state. they are marauders. eating insects. invertebrates. and fish Fry. The popularity of this species has waned in recent decennaries as much more colourful ( and frequently less hard-bitten ) species of gouramishave become widely available to hobbyists. This species is one of the few fish that can alter its colour ( lighter or darker ) in response to stimuli.
Eels are elongated fish. runing in length from 5 centimeter ( 2. 0 in ) in the one-jawed eel ( Monognathusahlstromi ) [ doubtful – discuss ] to 4 m ( 13 foot ) in the slender giant moray. [ 2 ] Adults scope in weight from 30 gms ( 1. 1 oz ) to good over 25 kgs ( 55 pound ) . They possess no pelvic fives. and many species besides lack thoracic fives. The dorsal and anal fives are fused with the caudal or tail five. organizing a individual thread running along much of the length of the animate being. Most eels live in the shallow Waterss of the ocean and tunnel into sand. clay. or amongst stones. A bulk of eel species are nocturnal. and therefore are seldom seen. Sometimes they are seen populating together in holes. or “eel pits” . Some species of eels besides live in deeper H2O on the Continental shelves and over the inclines deep as 4. 000 m ( 13. 000 foot ) . Lone members of the Anguilla household on a regular basis inhabit fresh H2O. but they excessively return to the sea to engender. Eels begin life as level and crystalline larvae. or leptocephali.
Eel larvae impetus in the surface Waterss of the sea. feeding onmarine snow. little atoms that float in the H2O. Eel larvae so transfigure into glass eels and so becomeelvers before eventually seeking out their juvenile and grownup home grounds. Freshwater elvers travel upstream and are forced to mount up obstructors. such as weirs. dike walls. and natural waterfalls. Lady Colin Campbell found. at Ballisodare. the eel piscaries were greatly improved by the hanging of slackly plaited grass ladders over barriers. enabling the elvers to go up. The heaviest true eel is the European conger. The maximal size of this species has been reported as making a length of 3 m ( 10 foot ) and a weight of 110 kilograms ( 240 pound ) . Other eels are longer but do non weigh as much. such as the slender giant moray which reaches 4 m ( 13 foot ) .
The guppy ( Poecilia reticulata ) . besides known as million fish and rainbow fish. [ 1 ] is one of the world’s most widely distributed tropical fish. and one of the most popularfreshwater fish tank fish species. It is a member of the Poeciliidae household and. like all other members of the household. is viviparous. [ 2 ] Guppies. whose natural scope is in nor’-east South America. were introduced to many home grounds and are now found all over the universe. They are extremely adaptable and thrive in many different environmental and ecological conditions. [ 3 ] Male rainbow fishs. which are smaller than females. have cosmetic caudal and dorsal fives. while females are duller in coloring material. Wild rainbow fishs by and large feed on a assortment of nutrient beginning including benthal algae and aquatic insectlarvae. [ 4 ] Guppies are used as a theoretical account being in the field of ecology. development. and behavioral surveies. [ 3 ]
They are the most fierce fish in the universe. Even the most formidable fish. the sharks or the barracudas. normally attack things smaller than themselves. But the marauder habitually attack things much larger than themselves. They will snarl a finger off a manus carelessly trailed in the H2O ; they mutilate swimmers—in every river town in Paraguay there are work forces who have been therefore mutilated ; they will rip and devour alive any hurt adult male or animal ; for blood in the H2O excites them to madness. They will rupture hurt wild poultry to pieces ; and seize with teeth off the dress suits of large fish as they grow exhausted when contending after being aquiline. But the marauder is a short. deep-bodied fish. with a blunt face and a to a great extent underhung or projecting lower jaw which gapes widely. The razor-edged dentitions are cuneate like a shark’s. and the jaw muscles possess great power.
The rabid. ferocious catchs drive the dentitions through flesh and bone. The caput with its short muzzle. gazing malignant eyes. and goggling. cruelly armed jaws. is the incarnation of evil fierceness ; and the actions of the fish precisely match its expressions. I ne’er witnessed an exhibition of such impotent. barbarous rage as was shown by the marauder as they flapped on deck. When fresh from the H2O and thrown on the boards they uttered an extraordinary squealing sound. As they flapped about they bit with barbarous avidity at whatever presented itself. One of them flapped into a fabric and seized it with a bulldog clasp.
Another grasped one of its chaps ; another snapped at a piece of wood. and left the teeth-marks deep therein. They are the plagues of the Waterss. and it is necessary to be extremely cautious about either swimming or wading where they are found. If cowss are driven into. or of their ain agreement enter. the H2O. they are normally non molested ; but if by opportunity some remarkably large or fierce specimen of these awful fishes does seize with teeth an animal—taking off portion of an ear. or possibly of a nipple from the bag of a cow—the blood brings up every member of the famished multitude which is anyplace close. and unless the attacked animate being can instantly do its flight from the H2O it is devoured alive. [ 28 ]
A tuna is a saltwater finfish that belongs to the folk Thunnini. a sub-grouping of the mackerel household ( Scombridae ) – which together with the tunas. besides includes the bonitos. mackerels. and Spanish mackerels. Thunnini comprises 15 species across five genera. [ 1 ] the sizes of which vary greatly. runing from the slug tuna ( soap. length: 50 centimeter ( 1. 6 foot ) . weight: 1. 8 kilogram ( 4 pound ) ) up to theAtlantic bluefin tuna ( soap. length: 4. 6 m ( 15 foot ) . weight: 684 kilogram ( 1. 508 pound ) ) . The bluefin averages 2 m ( 6. 6 foot ) . and is believed to populate for up to 50 old ages. Their circulatory and respiratory systems are alone among fish. enabling them to keep a organic structure temperature higher than the encompassing H2O. An active and nimble marauder. the tuna has a sleek. streamlined organic structure. and is among the fastest-swimming oceanic fish – the Thunnus albacares tuna. for illustration. is capable of velocities of up to 75 kilometers per hours ( 47 miles per hour ) . [ 2 ] Found in warm seas. it is extensively fished commercially and is popular as a game fish. As a consequence of over-fishing. stocks of some tuna species. such as the Southern bluefin tuna. have been reduced perilously near to the point of extinction. [ 3 ]
The dunce sharks are a group of sharks in the household Sphyrnidae. so named for the unusual and typical construction of their caputs. which are flattened and laterally extended into a “hammer” form called a “cephalofoil” . Most hammerhead species are placed in the genus Sphyrna while the winghead sharkis placed in its ain genus. Eusphyra. Many non needfully reciprocally sole maps have been proposed for the cephalofoil. including centripetal response. maneuvering. and prey use. Dunces are found worldwide in heater Waterss along coastlines and Continental shelves. Unlike most sharks. dunces normally swim in schools during the twenty-four hours. going lone huntsmans at dark. Some of these schools can be found near Malpelo Island in Colombia. Cocos Island off Costa Rica. and near Molokai Island in Hawaii. Large schools are besides seen in southern and eastern Africa.
Starfish or sea stars are asteroid echinoderms belonging to the classAsteroidea. Common use often finds these names being besides applied toophiuroids. which are right referred to as “brittle stars” or “basket stars” . About 1. 500 species of starfish occur on the seabed in all the world’s oceans. from the Torrid Zones to frigid polar Waterss. They are found from the intertidal zonedown to abyssal deepnesss. 6. 000 m ( 20. 000 foot ) below the surface. Starfish are marine invertebrates. They typically have a cardinal phonograph record and five weaponries. though some species have more than this. The
aboral or upper surface may be smooth. farinaceous or spinous. and is covered with overlapping home bases. Many species are brilliantly coloured in assorted sunglassess of ruddy or orange. while others are bluish. Grey or brown. Starfish have tube pess operated by a hydraulic systemand a oral cavity at the Centre of the unwritten or lower surface. They are opportunisticfeeders and are largely marauders on benthal invertebrates.
Several species have specialized eating behaviors including eversion of their stomachs andsuspension feeding. They have complex life rhythms and can reproduce both sexually and asexually. Most can renew damaged parts or lost weaponries and they can cast weaponries as a agency of defense mechanism. The Asteroidea occupy several important ecological functions. Starfish. such as the ocher sea star ( Pisaster ochraceus ) and the reef sea star ( Stichaster australis ) . have become widely known as illustrations of the anchor species construct in ecology. The tropicalcrown-of-thorns sea star ( Acanthaster planci ) is a rapacious marauder of coralthroughout the Indo-Pacific part. and the northern Pacific sea star is considered to be one of the world’s 100 worst invasive species.
The dodo record for starfish is ancient. dating back to the Ordovician around 450 million old ages ago. but it is instead hapless. as starfish tend to disintegrate after decease. Merely the bonelets and spinal columns of the animate being are likely to be preserved. doing remains difficult to turn up. With their appealing symmetrical form. sea star have played a portion in literature. fable. design and popular civilization. They are sometimes collected as oddities. used in design or as logos. and in some civilizations. despite possible toxicity. they are eaten.