Fish vary greatly in size. The extant whale shark and basking shark exceed all other fish by a considerable margin in weight and length. With the extinct Otodus megalodon exceeding all other fish extant and extinct (excluding tetropods) in size.^[1] Fish are a paraphyletic group that describes aquatic vertebrates while excluding tetrapods, and the bony fish that often represent the group are more closely related to tetropods such as whales, than to the cartilaginous fish such as sharks and rays. ^{[citation needed]} As such, cross group comparisons on this page only serve a colloquial purpose.

Rank	Name	Binomial name	Taxonomic class	Known maximum mass [tonnes]	Maximum length [m (ft)]	Images	Size comparison to human
1	Whale shark	Rhincodon typus	Chondrichthyes (Cartilaginous fish)	21.5[2]	18.8 metres (61.7 ft)[3]
2	Basking shark	Cetorhinus maximus	Chondrichthyes (Cartilaginous fish)	5.2 (16 unconfirmed)[2]	14 metres (46 ft)[2][4][5]
3	Great white shark	Carcharodon carcharias	Chondrichthyes (Cartilaginous fish)	3.324[6]	7 metres (23 ft)[7]
4	Tiger shark	Galeocerdo cuvier	Chondrichthyes (Cartilaginous fish)	3.11 (unconfirmed)[8][9]	7.5 metres (25 ft)[10] (unconfirmed)
5	Giant oceanic manta ray	Mobula birostris	Chondrichthyes (Cartilaginous fish)	3.0[11]	5 metres (16 ft)[11]
6	Giant sunfish	Mola alexandrini	Osteichthyes (Bony fish)	2.744[12]	3.3 metres (11 ft)[13]
7	Ocean sunfish	Mola mola	Osteichthyes (Bony fish)	2.3[2]	3.1 metres (10 ft)[2]
8	Beluga sturgeon	Huso huso	Osteichthyes (Bony fish)	2.072[14]	7.2 metres (24 ft)[15]
9	Sharptail mola	Masturus lanceolatus	Osteichthyes (Bony fish)	2[16]	3.0 metres (9.8 ft)[16]
10	Hoodwinker sunfish	Mola tecta	Osteichthyes (Bony fish)	1.87[citation needed]	2.4 metres (7.9 ft)[citation needed]
11	Reef manta ray	Manta alfredi	Chondrichthyes (Cartilaginous fish)	1.4[17]	5.5 metres (18 ft)[17]
12	Greenland shark	Somniosus microcephalus	Chondrichthyes (Cartilaginous fish)	1.397[2]	7.3 metres (24 ft)[18]
13	Megamouth shark	Megachasma pelagios	Chondrichthyes (Cartilaginous fish)	1.215[19]	5.2 metres (17 ft)[19]
14	Kaluga	Huso dauricus	Osteichthyes (Bony fish)	1.140[2]	5.6 metres (18 ft)[2]

• Hagfish (Myxini)

The hagfish, which are not taxonomically true fish, are among the most primitive extant vertebrates. There is only one order and family in this animal class. All of the 77 known species have elongated, eel-like bodies but can be distinguished by their downward-facing mouths. The largest form is the Goliath hagfish (Eptatretus goliath). This species can range up to 1.28 m (4.2 ft) in length and weigh to 6.2 kg (14 lb).^[20]

• Lampreys (Petromyzontiformes)

As with the hagfish, lampreys appear eel-like in shape. They have cartilaginous skeletons and have been evolving separately from any other group for over 400 million years. They are predatory and often attach themselves to a fish or other small animal and gradually drain blood and organs. The largest species is the sea lamprey (Petromyzon marinus), which can grow to 1.2 m (3.9 ft) and weigh 2.5 kg (5.5 lb).^[21]

The largest fish of the now-extinct class Placodermi was the giant predatory Dunkleosteus. The largest and most well known species was D. terrelli, which grew almost 4.1 m (13.5 ft) in length^[22] Engelman (2023), using an ellipsoid volumetric method, estimated weights of 950–1,200 kilograms (2,090–2,650 lb) for typical (3.41 metres (11.2 ft) long) adult Dunkleosteus, and weights of 1,494–1,764 kilograms (3,294–3,889 lb) for the largest (4.1 metres (13.5 ft)) individual. ^[23][24][25] Its filter feeding relative, Titanichthys, may have rivaled it in size.^[26] Titanichthys reached a length of 7 m (23 ft)^[27][28] though in older paper it was estimated at 7.5 m (25 ft).^[29] However, according to a 2023 paper, it would have been the same size as Dukleosteus.^[25][23][24]

The cartilaginous fish are not directly related to the "bony fish," but are sometimes lumped together for simplicity in description. The largest living cartilaginous fish, of the order Orectolobiformes, is the whale shark (Rhincodon typus), of the world's tropical oceans. It is also the largest living animal that is not a cetacean and, like the largest whales, it is a docile creature that filter-feeds on tiny plankton. An average adult of this species measures 9.7 m (32 ft) long and weighs an average of 9 tonnes. The largest verified specimen was caught in 1949 off Karachi, Pakistan and was 12.7 m (42 ft) long and weighed 21.5 tonnes (21.2 long tons; 23.7 short tons). Although many are dubious, there are several reports of larger whale sharks, with reliable sources citing unverified specimens of up to 37 tonnes (36 long tons; 41 short tons) and 17 m (56 ft)^[2][30] or possibly up to 21.9 metres (72 ft).^[31]

The extinct Megalodon is estimated to have been the largest Cartilagenous fish as well as largest non-tetrapod fish. It was macropredatory feeding mainly on marine mammals.^[32][33][34] With maximum total length estimates ranging from 14.3–24.3 metres (47–80 ft).^[35][36][37]

• Ground sharks (Carcharhiniformes)

The largest species of this order is the widely distributed tiger shark (Galeocerdo cuvier). Specimens have been verified to at least 5.5 m (18 ft) but even larger ones have been reported. One specimen, a gravid female caught off Australia and measuring only 5.5 m (18 ft) long, weighed an exceptional 1,524 kg (3,360 lb).^[2] A female caught in 1957 reportedly measured 7.4 m (24 ft) and weighing 3,110 kg (6,860 lb), although this very outsized shark is not known to have been confirmed.^[38] The largest of the "requiem sharks" (in the genus Carcharhinus) seems to be the dusky shark (C. obscurus), at up to 4.2 m (14 ft) and a weight of 350 kg (770 lb).^[39] However, the bulkier bull shark (C. leucas) has been estimated to weigh about 575 kg (1,268 lb) in recent specimens that measured over 4 m (13 ft) long.^[40] The silky shark (C. falciformis) is another contender for the largest requiem shark at a maximum weight of 350 kg (770 lb) and a maximum length of around 3.5 m (11 ft). The largest hammerhead shark is the great hammerhead (Sphyrna mokarran), which can reach 6.1 m (20 ft) and weigh at least 500 kg (1,100 lb).^[41] The most species-rich shark family, the catsharks, are fairly small-bodied. The largest, the nursehound (Scyliorhinus stellaris), can grow up to 1.7 m (5.6 ft) and a weight of at least 10.8 kg (24 lb).^[42][43]

• Chimaeras (Chimaeriformes)

These odd, often translucent cartilaginous fish are typically quite small. The largest species is the carpenter's chimaera (Chimaera lignaria) of the oceans near Australia and New Zealand. It can reach up to 1.5 m (4.9 ft) in length and weigh 15.4 kg (34 lb).^[44]

• Frill sharks and cow sharks (Hexanchiformes)

The largest frill sharks and cow shark is the Bluntnose sixgill shark (Hexanchus griseus). This large species typically inhabits depths greater than 90 m (300 ft), and has been recorded as deep as 1,875 m (6,152 ft). The largest specimen known (caught off Cuba) reportedly weighed 763 kg (1,682 lb) and measured 4.82 m (15.8 ft) long.^[2]

• Bullhead sharks (Heterodontiformes)

These tropical, small sharks are noted for their broad head shape. The largest species is the Port Jackson shark (Heterodontus portusjacksoni) of Australasian waters, at up to 1.65 m (5.4 ft) long and weighing up to 20 kg (44 lb).^[45]

• Mackerel sharks (Lamniformes)

Most species in this order grow quite large. The largest living species is the basking shark (Cetorhinus maximus) of the world's northern temperate oceans, also the second largest fish. The largest specimen, which was examined in 1851, measured 12.3 m (40 ft) long and weighed 16 tonnes.^[2] Perhaps the most famous "big fish" is the great white shark (Carcharodon carcharias). Specimens have been measured up to 6.4 m (21 ft) and weighing 3,312 kg (7,302 lb), with great whites of at least 7 m (23 ft) long generally accepted.^[2][46] The common thresher (Alopias vulpinus), can grow to 7.6 m (25 ft) and weigh over 510 kg (1,120 lb), but much of its length is comprised by its extreme tail.^[47][48] Odd and recently discovered giants also live in this order: the slender, sword-snouted goblin shark (Mitsukurina owstoni), with unweighed specimens of up to approximately 6.17 m (20.2 ft), and the massive megamouth shark (Megachasma pelagios), up to 5.6 m (18 ft) long and a weight of 1,215 kg (2,679 lb).^[49][50]

The largest shark in the fossil record is the megalodon (Otodus megalodon), a colossal Neogene lamniform. The range of estimates of the maximum length for megalodon are from 17 to 24.3 m (56 to 80 ft), with a mass ranging from 65 to 114 short tons (59 to 103 t).^{[51][52][53][54]} It is also regarded as the largest macro-predatory fish ever.

• Stingrays and allies (Myliobatiformes)

Both the largest species of this order and the largest of all rays is the giant oceanic manta ray (Manta birostris). This peaceful leviathan can reach a size of 3,000 kg (6,600 lb), a "disk" width of 9.1 m (30 ft) and a total length of 5 m (16 ft).^[55] A related species reaches barely smaller sizes, the devil fish (Mobula mobular). It can grow up to a 5.2 m (17 ft) disk width, a total length of 6.5 m (21 ft) and a weight of at least 1,000 kg (2,200 lb).^[56][57] The largest stingray is generally accepted to be the short-tail stingray (Dasyatis brevicaudata), found off the southern tip of Africa and Australasia, at up to 4.3 m (14 ft) across the disk and weighing more than 350 kg (770 lb).^[58] Although there are several large stingrays that at least approach this species' size. One, the giant freshwater stingray (Himantura polylepis), of the large rivers of South Asia, can weigh up to 600 kg (1,300 lb), measure up to 5 m (16 ft) in total length and have a disc span of 2.4 m (7.9 ft).^[59][60]

• Carpet sharks (Orectolobiformes)

The whale shark is the largest species in this order, reaching up to 20 meters long when fully mature.^[61] No other species in the order even approaches this size. The next largest species is the nurse shark (Ginglymostoma cirratum), which can grow up to 4.3 m (14 ft) across the disk and weighing more than 350 kg (770 lb).^[62]

• Sawfish (Pristiformes)

Distinguished by a long snout decorated with sharp teeth on the sides, these little-known cartilaginous fish are often reported to attain huge sizes. The definitive largest species is not known, although the smalltooth sawfish (Pristis pectinata) and the green sawfish (P. zijsron), at up to reportedly 7.6 and 7.3 m (25 and 24 ft), respectively, may be the largest.^[63][64] Weights of up to 1,955 kg (4,310 lb) have been reported, possibly for the smalltooth species, but are not verified.^[65] The large-tooth sawfish (P. pristis) and freshwater sawfish (P. microdon) can both exceed 6.5 m (21 ft).^[66][67]

• Sawsharks (Pristiophoriformes)

Despite sharing a similar appearing snout adapted in both to shred fish prey, the sawsharks are typically much smaller than sawfish. The largest sawshark is the Sixgill sawshark (Pliotrema warreni) of the South Indian ocean, which can grow up to 1.7 m (5.6 ft) and weigh 15 kg (33 lb).^[68]

• Skates and allies (Rajiformes)

The largest and most diverse order of rays' largest species is the giant guitarfish (Rhynchobatus djiddensis) of the Red Sea and the eastern Indian ocean. The top size of the species is 227 kg (500 lb) and 3.1 m (10 ft).^[69] The largest of the skates is the common skate (Dipturus batis). This species can grow up to 2.85 m (9.4 ft) in length and weigh 97.1 kg (214 lb).^[70]

• Dogfish and allies (Squaliformes)

The largest known member of this order is the Greenland shark (Somniosus microcephalus), a giant predator of sub-Arctic waters. This species has been confirmed to as much as 6.4 m (21 ft) in length and a weight of 1,397 kg (3,080 lb), although specimens of up to 7.3 m (24 ft) have been reportedly caught.^[2][71] The Pacific sleeper shark (Somniosus pacificus) has been measured only to 4.4 m (14 ft) and 888 kg (1,958 lb) in a gravid female, although specimens up to an estimated 7 m (23 ft) have been scientifically observed.^[2][72] A single unconfirmed account exists of an enormous Pacific sleeper shark that potentially measured up to 9.2 m (30 ft) long.^[73] The spiny dogfish (Squalus acanthias), a very common species, reaches the largest sizes of the "true dogfish" family. Specimens have been measured at up to 1.6 m (5.2 ft) and 9.1 kg (20 lb).^[74]

• Angelsharks (Squatiniformes)

The largest of the bottom-dwelling angelsharks (named for their shape rather than disposition) is the common angelshark (Squatina squatina) of the northeast Atlantic Ocean. This species can grow up to 2.4 m (7.9 ft) long and weigh up to 80 kg (180 lb).^[75]

• Electric rays (Torpediniformes)

The largest of the electric rays is Atlantic torpedo (Torpedo nobiliana). This fish can measure 1.8 m (5.9 ft) long and weigh 90 kg (200 lb).^[76] However, a length of 0.6–1.5 m (2.0–4.9 ft) and weight of 30 pounds (14 kg) is more typical.^[77][78] Females attain a larger size than males.^[79]

The largest of the now-extinct Acanthodii was Xylacanthus grandis, an ischnacanthiform based on a ~35 cm (14 in) long jaw bone. Based on the proportions of its relative Ischnacanthus, X. grandis had an estimated total length of 2.5 m (8 ft 2 in).^[80]

The largest living bony fish (superclass Osteichthyes, which includes both ray-finned and lobe-finned fish) are the lesser known southern sunfish (Mola alexandrini) followed by widely distributed and better known ocean sunfish (Mola mola) and, both being members of the order Tetraodontiformes. The largest verified specimen belongs to the southern sunfish discovered dead near the Azores in the Atlantic has set the record for being the largest extant bony fish with the weight of 2,744 kg (6,049 lb). The record size ocean sunfish crashed into a boat off Bird Island, Australia in 1910 and measured 4.3 m (14 ft) from fin-to-fin, 3.1 m (10 ft) in length and weighed about 2,300 kg (5,100 lb),^[2] while the other record for the biggest bony fish is yet held by a Mola alexandrini which was also coincidentally 2,300 kg (5,100 lb) in mass and 3 m (9.8 ft) in length, caught off in 1996 and misidentified as a Mola mola.

As for length, the longest extant bony fish on earth is the giant oarfish (Regalecus glesne). Slender and compressed, it averages over 6 m (20 ft) long at maturity. A specimen caught in 1885 of 7.6 m (25 ft) in length weighed 275 kg (606 lb). The longest known example, which was hit by a steamship, was measured as 13.7 m (45 ft) long.^[2]

Much larger bony fish existed prehistorically, the largest ever known having been Leedsichthys of the Jurassic period. This species is certainly the largest bony fish ever and one of the largest non-cetacean marine animals to have ever existed. Estimates of the size of this fish range from 21 to 27 m (69 to 89 ft) and mass from 20 to 50 tons. A maximum size of 22 m (72 ft) and 25–30 tons had been deemed to be most realistic.^[81] However, a 2013 study which estimated the maximum size of the animal based on the largest specimens it is estimated that Leedsichthys would have a maximum length of 16.5 metres (54 ft) and a maximum weight of 49 tonnes (108,000 lb).^[82]

• Sturgeons and paddlefishes (Acipenseriformes)

The largest species is the beluga sturgeon (Huso huso) of the Caspian and Black seas, the only extant bony fish to rival the massiveness of the ocean sunfish. The largest specimen considered reliable (based on remains) was caught in the Volga estuary in 1827 and measured 7.3 m (24 ft) and weighed 1,474 kg (3,250 lb).^[2] The slightly smaller kaluga (Huso dauricus) or great Siberian sturgeon has been weighed reliably up to 1,140 kg (2,510 lb) (Berg, 1932) and a length of 5.6 m (18 ft).^[2][83] The North American white sturgeon (Acipenser transmontanus), unverified to 907 kg (2,000 lb) and 6.1 m (20 ft), Chinese, European oceanic, and the Russian sturgeon (A. gueldenstaedtii), at as much as 1,000 kg (2,200 lb) and 5.5 m (18 ft) for a 75-year-old female, also can attain great sizes.^[2] Atlantics and Baikal sturgeons are following as well. These fish are sometimes called the largest freshwater fish but sturgeons spend a great deal of time in brackish water and switch back and forth between saltwater and freshwater environments in their life cycle. Also included in this order are the paddlefish and the Chinese paddlefish (Psephurus gladius), which is now officially recognised as extinct by the IUCN (as of July 2022), is also a very large fish. Reportedly, fisherman as recently as the 1950s have caught paddlefish measuring up to 6.7 m (22 ft) in total length, although no specimen greater than 3.1 m (10 ft) has been scientifically measured. The weight of the Chinese paddlefish is reportedly 300 to 500 kg (660 to 1,100 lb).^[84][85]

• Bonefish (Albuliformes)

The largest Albuliformes is the bonefish (Albula vulpes), which weighs up to 19 lb (8.6 kg) and measures up to 90 cm (35 in) long. It is silvery in color with dusky fins. The bases of the pectoral fins are yellow.

• Bowfins (Amiiformes)

The bowfin (Amia calva) is one of 2 extant species of it's order, a long with the eyespot bowfin (Amia ocellicauda). The most distinctive characteristic of the bowfin is its very long dorsal fin consisting of 145 to 250 rays, and running from mid-back to the base of the tail. The caudal fin is a single lobe, though heterocercal.^[86] They can grow up to 109 cm (43 in) in length, and weigh 9.75 kg (21.5 lb).^[87]

• Eels (Anguilliformes)

The largest species of "true eel," if measured in weight and overall bulk, is the European conger (Conger conger). The maximum size of this species has been reported to 3 m (9.8 ft) and a mass of 110 kg (240 lb), but possibly up to 160 kg (350 lb).^[88][89] Several moray eels can equal or exceed the previous eel in length but do not weigh as much. The longest fish in the order, at up to 4 m (13 ft), is the slender giant moray (Strophidon sathete) of the Indo-Pacific oceans.^[90]

• Silversides (Atheriniformes)

An order best known for its tiny representatives, the Argentinian Silverside (Odontesthes bonariensis) is found primary in the freshwater bodies and brackish estuaries of Argentina and Chile, but also along the Argentinian coast. It is known locally as "pejerrey," a combination of the Spanish words for "fish" pez and "king" rey. The confirmed record stands at 76 cm (30 in) and 3.6 kg (7.9 lb), yet there are unconfirmed reports of the fish reaching up to 82 cm (32 in) and 6.3 kg (14 lb).^[91] The largest North American species of Silverside is the jacksmelt (Atherinopsis californiensis) of the Eastern Pacific Ocean. It often reaches a maximum size of 49 cm (19 in), but possibly up to 55 cm (22 in).^[92] The largest recorded jacksmelt was 680 g (1.50 lb).^[93]

• Barreleyes, slickheads and argentines (Argentiniformes)

The largest species is the greater argentine (Argentina silus), that has 76 centimetres (30 in) TL.

The largest barreleyes are javelin spookfish (Bathylychnops exilis) found in the northern Pacific and in the eastern Atlantic Ocean near the Azores where it is found at depths of around 640 metres (2,100 ft). This species grows to a length of 50 centimetres (20 in) SL.^[94]

• Jellynose fishes (Ateleopodiformes)

Jellynose fish are benthic marine fish typically found at depths around 200 to 600 m (660 to 1,970 ft). Size ranges from 35 centimetres (14 in) (Ateleopus japonicus) to 2 meters (79 in) (Guentherus altivela^[95]).

• Grinners (Aulopiformes)

The largest member of this order is the lancetfish (Alepisaurus ferox), found in all the world's oceans. Slender, with a huge spine, these fish can reach 2.1 m (6.9 ft) long and can weigh up to 11 kg (24 lb).^[96]

• Toadfish (Batrachoidiformes)

The largest toadfish is the Pacuma toadfish (Batrachoides surinamensis), reaching a size of up to 2.4 kg (5.3 lb) and 58 cm (23 in).^[97]

• Flying-fish and allies (Beloniformes)

The largest member of this order, best known for its members' ability to breach the water and glide through the sky, is the pelagic Houndfish (Tylosurus crocodilus), a slender fish at up to 1.5 m (4.9 ft) and a weight of 6.35 kg (14.0 lb).^[98] The largest true "flying fish" is the Japanese flying fish (Cheilopogon pinnatibarbatus japonicus), which can range up to 0.5 m (1.6 ft) in length and weigh over 1 kg (2.2 lb).^[85]

• Squirrelfish (Beryciformes)

Best known for their highly poisonous barbs, the squirrelfish's largest representative is the giant squirrelfish (Sargocentron spiniferum) of the Indo-Pacific, at up to 51 cm (20 in) and 2.6 kg (5.7 lb).^[99] The slimmer Holocentrus adscensionis from warm parts of the Atlantic can reach even greater lengths of up to 61 cm (24 in).^[100]

• Whalefish (Cetomimiformes)

Known for flesh that feels flabby to the touch, this order reaches largest sizes in the flabby whalefish (Gyrinomimus grahami) of all southern oceans. This species, which can range up to 0.45 m (1.5 ft) in length and weigh 1.5 kg (3.3 lb), is sometimes commercially fished.^[85][101]

• Characins (Characiformes)

The largest species is the African freshwater fish, the giant tigerfish (Hydrocynus goliath). The top size of this fish is 1.5 m (4.9 ft) and 50 kg (110 lb).^[102][103] Among the largest of the characin family is the popular sport-fish, the golden dorado (Salminus brasiliensis), which can reach up to 1 m (3.3 ft) in length and weigh 31.4 kg (69 lb).^[104] Among the characins are the infamous neotropical piranhas. Carnivorous species can grow up to 0.43 m (1.4 ft), although the Tambaqui (Colossoma macropomum), also known as the pacu, at up to 1 m (3.3 ft) and 32.4 kg (71 lb), is often considered a giant, herbivorous form of piranha.^[85]

• Herring (Clupeiformes)

The largest herring is probably the Dorab wolf herring (Chirocentrus dorab) of the Indo-Pacific oceans. The maximum size of this species has been reported as much as 1.8 m (5.9 ft), but these slender fish have never been recorded as exceeding 3.4 kg (7.5 lb) in weight.^[85] The so-called "king of herrings" is not a herring, but an oarfish.

• Minnows and allies (Cypriniformes)

The minnow family (which includes carp), Cyprinidae, is the largest family of vertebrates, with over 2400 species known today.^[105] The largest species is the giant barb (Catlocarpio siamensis), which is endemic to three river basins in southeast Asia and reaches a size of as much as 3 m (9.8 ft) and a weight of as much as 300 kg (660 lb).^[106] In centuries past, mahseer, specifically the golden mahseer (Tor putitora) of Southern Asia was reported to reach similar lengths, but the species has been overfished and specimens nearly as large as the giant barb have not been reported in recent centuries.^[85][107]

• Pikes and allies (Esociformes)

The largest species in this small but interesting order (formerly allied with the salmonids) is the muskellunge (Esox masquinongy) of the rivers of North America. These predatory fish can grow up to 1.8 m (5.9 ft) and 31.8 kg (70 lb).^[108][109]

• Killifish and allies (Cyprinodontiformes)

The largest species in this relatively small-bodied order is the Pacific four-eyed fish (Anableps dowei), reaching a size of 34 cm (13 in) and 588 g (1.296 lb).^[110]

• Ladyfish and allies (Elopiformes)

This small order is usually considered closely related to the true eels although its members are very different in appearance and behavior from eels. The largest species is much-coveted-sport fish, the Atlantic tarpon (Megalops atlanticus). The maximum recorded size for this species is 161 kg (355 lb) and a length up to 2.5 m (8.2 ft).^[111]

• Cod (Gadiformes)

The Atlantic cod (Gadus morhua) grows to 2 m (6.6 ft) long and 96 kg (212 lb).^[112]

• Sticklebacks and allies (Gasterosteiformes)

The largest form of stickleback, a small, cylindric type of fish, is the sea stickleback or fifteenspine stickleback (Spinachia spinachia). This species can range up to 22 cm (8.7 in) in length and weigh up to 8.5 g (0.30 oz).^[85][113]

• Clingfish (Gobiesociformes)

These bottom-dwelling fish reach their maximum size in Sicyases sanguineus. This species can reach 30 cm (12 in) in length and weigh up to 1 kg (2.2 lb).^[85]

• Shellears and allies (Gonorynchiformes)

The well-known milkfish (Chanos chanos) is the largest member of this order. The maximum size is 22.7 kg (50 lb) and 1.84 m (6.0 ft) long.^[85]

• Knifefish (Gymnotiformes)

The largest knifefish is recently classified Volta's electric eel (Electrophorus voltai), a species of electric eel in the genus Electrophorus, which previously only had the electric eel (Electrophorus electricus), but now contains 3 species. The electric eels have an elongated, cylindrical body, with their anus near the front of the body.

E. voltai can reach up to 2.5 m (8 ft 2 in) and 22 kg (49 lb), making them the largest species of the Gymnotiformes. They can impressively emit up to 860 volts out of their body.^[114]

E. electrius typically grows to about 2 m (6 ft 7 in) in length, and 20 kg (44 lb) in weight.^[115]

• Mooneyes (Hiodontiformes)

Only two extant species are known to exist in this relatively new order. The larger of the two is the goldeye (Hiodon alosoides) from the northern rivers of North America, which can reach up to 0.5 m (1.6 ft) in length and can weigh 1.8 kg (4.0 lb).^[116][117]

• Ribbonfish and allies (Lampriformes)

The largest member of this small but fascinating order is the aforementioned king of herrings or giant oarfish (Regalecus glesne), the longest extant bony fish on earth, ranging from 7–8 metres (23–26 ft) total length, likely up to 11 metres (36 ft), and can be as heavy as 272 kg (600 lb). Another interesting big fish in this order is the opah (Lampris guttatus), which as opposed to the king of herrings, is massive and has a chunky, rounded shape. Opahs can range up to 2 m (6.6 ft) in length and weigh up to 270 kg (600 lb).^[118]

• Gars (Lepisosteiformes)

The largest of the gar, and the largest entirely freshwater fish in North America, is the alligator gar (Atractosteus spatula). The largest gar ever known, caught in Louisiana in 1925, was 3 m (9.8 ft) in length and weighed 137 kg (302 lb).^[2]

• Anglerfish (Lophiiformes)

The largest of this diverse order is the common goosefish (Lophius piscatorius) found in the northeastern Atlantic off Europe and North Africa. This big-mouthed fish can attain a size of 58 kg (128 lb) and a length of 2 m (6.6 ft).^[119]

• Lanternfish (Myctophiformes)

The largest of the numerous but small lanternfish is Bolin's lanternfish (Gymnoscopelus bolini) of the Indo-Pacific oceans, at up to 249 g (8.8 oz) and 35 cm (14 in).^[85]

• Mullets (Mugiliformes)

The largest of mullets flathead mullet (Mugil cephalus) have dark centers which give the appearance of a series (6–7) of dark horizontal stripes. The fish grow to lengths up to 60.0 cm (23.6 in) with weights as high as 4.0 kg (8.8 lb).

• Pearlfish and allies (Ophidiiformes)

The largest member of this order is the widely distributed giant cusk-eels (Lamprogrammus shcherbachevi). A cuskeel can be nearly 2 m (6.6 ft) long, but even large fish probably aren't much over 10 kg (22 lb) since they are quite slender.^[85]

• Smelts and allies (Osmeriformes)

The largest smelt is the rainbow smelt (Osmerus mordax). The body of the rainbow smelt is slender and cylindrical. When full grown, the rainbow smelt is between 7 and 9 inches (18 and 23 cm) long and weighs about 3 ounces (85 g). Individuals over 12 inches (30 cm) long are known.^[120]

• Bony-tongued fish (Osteoglossiformes)

The largest species is the South American fish usually known as the arapaima (Arapaima gigas). The maximum size this species can attain is a matter of some controversy and some rank it among the world's largest freshwater fishes. No individual arapaima over 3 m (9.8 ft) has been verified and measured. The skeleton of a fish reported to have been measured by native hunters as 4.5 m (15 ft) and weighing 200 kg (440 lb) when caught, was later examined as a skeleton scientifically and was found to have been roughly within that outsized dimension.^[2]

• Perches and allies (Perciformes)^{[dubious – discuss]}

The title of the largest member of this order, the most numerous order of all vertebrates, is a matter of some debate. A large marlin is the biggest of these fishes: the black marlin (Makaira indica) of the Indo-Pacific, the Atlantic blue marlin (Makaira nigricans) and the Indo-Pacific blue marlin (Makaira mazara). All of these similarly sized species can exceptionally reach up to 5 m (16 ft) in length and weight may be as much as 907 kg (2,000 lb) or even 1,106 kg (2,438 lb).^{[85][121][122]} Another notable giant of the perch order is the Atlantic bluefin tuna (Thunnus thynnus) of the Northern Atlantic ocean, which has been verified at up to 4.4 m (14 ft) and 679 kg (1,497 lb), although can reportedly reach 910 kg (2,010 lb).^[123][124] The swordfish (Xiphias gladius) can reach a maximum weight of 650 kg (1,430 lb) and length of 4.5 m (15 ft).^[125] Due to heavy fishing of both species, swordfish and tuna of great sizes are increasingly rare.

One of the largest freshwater fishes is the Nile perch (Lates niloticus), which grows up to 200 kg (440 lb) and 2 m (6.6 ft), and is the largest of the suborder Centropomoidei.^[126]

Also in the suborder Centropomoidei, the largest barracuda is the great barracuda (Sphyraena barracuda) reaching 46 kg (101 lb), and the largest snook is the black snook (Centropomus nigrescens) reaching up to 27 kg (60 lb).

The biggest of snappers is the Cubera snapper (Lutjanus cyanopterus) of the Caribbean sea and east coast of South America, at a maximum size of 57 kg (126 lb) and 1.6 m (5.2 ft) in length.^[127][128]

The largest species of grunt is the white margate (Haemulon album) of the Caribbean sea and east coast of South America, at up to 7.14 kg (15.7 lb) and 0.8 m (2.6 ft) in length.^[129][130]

The blennies can range up to 0.55 m (1.8 ft) in the hairtail blenny (Xiphasia setifer) of the Indo-Pacific.^[85]

The spanish mackerels reach their maximum size in the Chinese seerfish (Scomberomorus sinensis), which can attain a size of 131 kg (289 lb) and 2.47 m (8.1 ft).^[131][132] They are closely related to tunas of the tribe Thunnini.

The largest of diverse family of trevallies, jacks, or jack mackerels (carangidae) is the greater amberjack (Seriola dumerili) reaching a published size of 80 kg (175 lb), but likely up to 100 kg (220 lb).^[133][134] The giant trevally (Caranx ignobilis) is often also cited as the largest in carangidae, and can reach a weight of 80.5 kg (177 lb).^[135]

The largest butterflyfish are either the lined butterflyfish (Chaetodon lineolatus) or the saddle butterflyfish (C. ephippium), both of the Indo-Pacific and both of which can measure up to 30 cm (12 in).^[136]

Within the percidae family, namesake of the Perciformes order, the largest fish is the Zander (Sander lucioperca) which can weigh up to 18.7 kilograms (41 lb 4 oz).^[137] The popular North American walleye (Sander vitreus) can reach a maximum weight of 11.5 kilograms (25 lb).^[138]

The freckled darter (Percina lenticula) of the United States, the biggest of the darters (under the percidae family), reaching 20 cm (7.9 in) and 70 g (2.5 oz).^[139][140]

The largest drum/croaker (Sciaenidae) is the Totoaba (Totoaba macdonaldi) of the Gulf of California, at up to 100 kg (220 lb) and 2 m (6.6 ft) long.^[141] Some other notable large fish from this family are the mulloway/ Dusky Kob (Argyrosomus japonicus) reaching a max size of 82 kg (181 lb), the black drum (Pogonias cromis), reaching a size of 51 kg (112 lb), and the red drum (Sciaenops ocellatus) with a size of 43 kg (95 lb).

Among the sea bass or groupers, many of which can grow quite large, the greatest size are reached in the Atlantic goliath grouper (Epinephelus itajara) and the giant grouper (Epinephelus lanceolatus). Both can reach a maximum known length of 2.6 m (8.5 ft) and weight of 455 kg (1,003 lb) and 400 kg (880 lb) respectively.^{[142][143][144]}

The giant seabass (Stereolepis gigas) of the Pacific ocean, the largest of the Acropomatiformes order, can attain a maximum published size of 255 kg (562 lb) but may reach up to 270 kg (600 lb), with a maximum length of 2.3 m (7.5 ft).^[145]

The species-rich cichlids reach their maximum size in the East African giant cichlid (Boulengerochromis microlepis), at up to 0.9 m (3.0 ft) long and 5 kg (11 lb).^[146]

The humphead wrasse (Cheilinus undulatus) of the Indo-Pacific's coral reefs is by far the largest wrasse, and it can reach a maximum size of 191 kg (421 lb) and 2.3 m (7.5 ft).^[147]

Among a fairly small-bodied family, the damselfishes, the Garibaldi (Hypsypops rubicundus) of the Pacific coast of America is the biggest, reaching up to 35.5 cm (14.0 in) and 1.2 kg (2.6 lb).^[148]

The marbled sleeper (Oxyeleotris marmorata) of East Asia is the largest member of the Gobiiformes, and can reach 0.66 m (2.2 ft) long and weigh 9.9 kg (22 lb).^[85][149]

The largest species of surfperch (Embiotocidae) is the barred surfperch (Amphistichus argenteus) which can reach a length of 49.5 cm (19.5 in) with a weight of 2.15 kg (4.7 lb).^[150]

• Trout-perch and allies (Percopsiformes)

The largest species in this small order (both by number of species and body size) is the sand roller (Percopsis transmontana) of North America. This species can range up to 20 cm (7.9 in) in length and can weigh over 11 g (0.39 oz).^[85]

• Flatfish (Pleuronectiformes)

The largest of the well-known and heavily fished flatfish is the Pacific halibut (Hippoglossus stenolepis). This giant can reach 363 kg (800 lb) and 3 m (9.8 ft), although fish even approaching this size would be extraordinary these days.^[151] The Atlantic halibut (Hippoglossus hippoglossus) is also sometimes titled the largest flatfish, although it has a slightly smaller maximum size, at 320 kg (710 lb) and 2.8 m (9.2 ft).^[85][152]

• Beardfish (Polymixiiformes)

The little-known beardfish are sometimes classified with the Beryciformes. The largest beardfish is Polymixia busakhini of the Indo-Pacific, which can range up to 0.6 m (2.0 ft) in length.^[85]

• Polypterids and allies (Polypteriformes)

The largest polypterid is the Congo bichir (Polypterus congicus), which reaches up to 97 cm (38 in) in length.^[153]

• Gulper eels (Saccopharyngiformes)

The largest gulper eel is the pelican eel (Eurypharynx pelecanoides). The pelican eel grows to about 1 m (3.3 ft) in length.

• Salmon and allies (Salmoniformes)

The largest species of salmonid is the Siberian taimen (Hucho taimen). The biggest recorded taimen was caught in the Kotui River in Russia, and measured 2.1 m (6.9 ft) and weighed 105 kg (231 lb).^[154] Some sources claim the largest is the Chinook salmon (Oncorhynchus tshawytscha) of America's Pacific Northwest, although this species falls behind the taimen in maximum size.^[85] The maximum size of this fish is 61.4 kg (135 lb) and 1.5 m (4.9 ft) long.^[155]

• Sculpins, Lionfish, Rockfish, and allies (Scorpaeniformes)

The order scorpaeniformes, known for their venomous spines and benthic lifestyle, has a large variety of subfamilies and over 1320 species. This order has also been classified as a suborder under perciformes.^{[dubious – discuss]}

Although less venomous than many smaller fish in the same order, the skilfish (Erilepis zonifer) of the North Pacific, is largest of the scorpaeniformes. The maximum size is 1.9 m (6.2 ft) and the weight can be up to 91 kg (201 lb).^[156] The Lingcod (Ophiodon elongatus) of the west coast of North America is sometimes listed as the largest in the order, but it is not known to exceed 1.5 m (4.9 ft) in length or 60 kg (130 lb) in weight,^[85][157] which still makes it the largest of the Hexagrammidae. The Cottidae family, also known as the true sculpins, has it's largest species in the cabezon (Scorpaenicthys marmoratus) of coastal North America, which can range up to 99 cm (39 in) and 14 kg (31 lb).^[85][158] For the Scorpaenidae family, which includes rockfish, lionfish, and stonefish, is the extremely long-lived shortraker rockfish (Sebastes borealis) reaching 120 cm (47 in) and at least 20 kg (44 lb), with one specimen reported at 28 kg (62 lb).^[159] The largest in the Platycephalidae family, also known as flatheads, is the dusky flathead (Platycephalus fuscus) growing to 120 cm (47 in) and 15 kg (33 lb).^[160]

• Catfish (Siluriformes)

Most authorities now give the crown of the largest catfish to the Mekong giant catfish, Pangasianodon gigas, which is also considered the heaviest completely freshwater fish.^[2] This fish has been recorded at sizes up to 350 kg (770 lb) and 3 m (9.8 ft).^{[161][162][163][164]} The closely-related Asian giant pangasius (Pangasius sanitwongsei) can grow to 3 m (9.8 ft) and 300 kg (660 lb).^[165] Another large species is the wels catfish (Silurus glanis) of Europe and Central Asia, which strongly rivals the proceeding species in weight and could possibly surpass them in length. While wels have been confirmed to 3.1 m (10 ft), other whiskered giants have been reliably reported to grow to 3.7 m (12 ft) and 265 kg (584 lb) and less reliably to 4.3 m (14 ft).^[2] In South America there also exists the piraíba (Brachyplatystoma filamentosum), which can reportedly reach up to 3.6 m (12 ft) and 200 kg (440 lb).^[166]

• Ridgeheads and allies (Stephanoberyciformes)

The largest ridgeheads Poromitra curilensis, a Pacific ridgehead related to the crested bigscale,^[167] at up to 18 centimetres standard length (SL; a measurement excluding the caudal fin).^[168] Most ridgeheads are well under 10 centimetres SL.

• Bristlemouths (Stomiiformes)

The largest of the deep-sea bristlemouths is the short-tailed barbeled dragonfish (Oppostomias micripnus). The top size of a female of this species is probably over 452 g (0.996 lb) and 50 cm (20 in) long.^[85] In species like the barbeled dragonfish (Idiacanthus atlanticus), the snake-like females can measure up to 0.5 m (1.6 ft) long, about 50 times as long as the male.^[169] Although Idiacanthus is much more slender and is lighter than Oppostomias.^[85]

• Swamp-eels (Synbranchiformes)

The tropic-dwelling swamp-eels, which are not closely related to true eels, reaches their largest size in the marbled swamp eel (Synbrachus marmoratus) of Central and South America. This fish can range up to 1.5 m (4.9 ft) and weigh 7 kg (15 lb).^[85]

• Seahorses and allies (Syngnathiformes)

The largest of this diverse order is the red cornetfish (Fistularia petimba), a long, thin species found in all tropical oceans. This fish can reach a length of 2 m (6.6 ft) and a weight of 4.65 kg (10.3 lb).^[85] The largest of the famous, petite seahorses is the big-belly seahorse (Hippocampus abdominalis) found off Australia and New Zealand, which can grow to 35 cm (14 in) high and weigh over 60 g (2.1 oz).^[170]

• Pufferfishes and allies (Tetraodontiformes)

The starry pufferfish (Arothron stellatus) is the largest pufferfish in the world, growing to a length of 48 in (120 cm). The largest freshwater pufferfish is the mbu pufferfish (Tetraodon mbu) from the Congo River basin. It attains lengths of 67 cm (26 in). As such, these fish are difficult to adequately house in captivity since they require a very large aquarium and appropriately scaled water filtration. At lengths up to 1 m (39 in), the stone triggerfish (Pseudobalistes naufragium) from the eastern Pacific is the largest triggerfish (Balistidae family), edging out the titan triggerfish (Balistoides viridescens) at 75 cm (30 in).^[171]

• Dories (Zeiformes)

The largest species of dory is the Cape dory (Zeus capensis) reaching a size of 90 cm (35 in) and a weight of 20 kg (44 lb).^[85][172]

The largest living (non-tetrapod) lobe-finned fish is the coelacanth. The average weight of the living West Indian Ocean coelacanth, (Latimeria chalumnae), is 80 kg (180 lb), and they can reach up to 2 m (6.6 ft) in length. Specimens can weigh up to 110 kg (240 lb). The largest lobe-finned fish of all time was Rhizodus at up to 7 m (23 ft).^[173]

• Lungfish (Dipnoi)

The largest lungfish, the African lungfish (Protopterus aethiopicus), is smooth, elongated, and cylindrical with deeply embedded scales. The tail is very long and tapers at the end. They can reach a length of up to 2 m (6.6 ft) and may weigh as much as 50 kg (110 lb).^[174][175] The pectoral and pelvic fins are also very long and thin, almost spaghetti-like.

• Megafauna
• List of longest fish
• Largest organisms
• Largest prehistoric animals