Fish (Franchise)

Fish are essential creatures - mostly in the background - to the entire How to Train Your Dragon Franchise.

Description
Fish are a large, diverse group of vertebrate aquatic creatures that bear gills and fins, and can reside in freshwater and seawater. Some species are even capable of breathing air with lung-like organs and can cross land for a short time. However, fish are almost entirely dependent on water. Fish as a group is extremely diverse, living in many water habitats across the world at a variety of temperatures. They range in size from barely visible to the size of a whale (which is a mammal, not a fish). They come in many colors and shapes.

In the How to Train Your Dragon Franchise, fish imagery is typically not very precise, and often a "generic" fish is shown rather than details of a specific species. The exception is in the game, School of Dragons, which is a science-based game. In that game, species information is detailed for educational purposes.

In the School of Dragons player quest "Learn About the Food Chain", Mulch mentions that fish eat mosquitoes, along with "breadcrumbs and worms".

Function
For the most part, in actuality and in the Franchise, a fish's use is for food. Humans have probably been eating fish since they came to be. In the Franchise, fish are also the main - or at least a significant portion of - diet of all dragons. Their desire to eat fish is in part how the Vikings are able to train them, starting with Toothless in the first movie, How to Train Your Dragon. Toothless seems especially fond of mackerel. One particular exception is most dragon species aversion to eel. Eel causes illness in most dragons.

To catch fish, dragons seem to have numerous hunting behaviors to accomplish this. Some dragons like Toothless simply stick their head into water and grab any fish present; however, Toothless was also grounded at this time and may have other behaviors when able to fly. Others, like the Monstrous Nightmare, dive into water and round up shoals of fish by circling around them. The Bewilderbeast gulps large amounts of fish before spitting them out into the air for its dragons to feed on. In the game, Dragons: Rise of Berk, dragons that are able to fish dive straight into the sea and disappear, reappearing with a mouth full of fish.

Angler Fish
"The male anglerfish is a lot smaller than the female. When the male anglerfish matures, its digestive system stops functioning."

- Fish Fact in School of Dragons

"The anglerfish is known to be one of the ugliest creatures on the planet."

- Fish Fact in School of Dragons

Angler Fish are saltwater fish seen in the game, School of Dragons fishing activity. In game, the player must fly out to sea on a Gronckle with a special Deep-sea fishing rod to catch these fish. Only Gronckles can be used, because they are able to hover on one place over the sea.

In Dragons: Rise of Berk, an Angler Fish is an item that can be found by the Purple Death and used to complete Marooned Dragons collections.

"An anglerfish's skin and bones are very thin and flexible, thus allowing it to eat larger prey."

- Fish Fact in School of Dragons

"The female angler fish has a spine like a fishing rod, that supports a light producing organ known as photophore. Through a chemical process known as bioluminiscence, the photo"

- Fish Fact in School of Dragons

"When a male anglerfish can no longer eat, it finds a female and hooks itself to her using its teeth. He releases an enzyme that fuses their blood vessels together."

- Fish Fact in School of Dragons

Anglerfish are actually a large group of fish of the Order Lophiiformes. and occur worldwide. In actuality, Monkfish are a type of commercially important Anglerfish in Scandinavian seas. Monkfish differ in appearance, though, to the one portrayed in School of Dragons.

Arctic Char
Arctic Char are a fresh and saltwater species seen in the game, School of Dragons fishing activity. They can be fished for in arctic locations in the game, and were introduced to the game at the release of Icestorm Island.

"The Arctic Char can grow up to about 42 inches and weigh up to 33 pounds."

- Fish Fact from School of Dragons

"The diet of the Arctic char is mainly composed of small fish, amphipods, planktonic crustaceans, mollusks, and insects."

- Fish Fact from School of Dragons

"The Arctic Char is a part of the Salmonidae family and is similar to a salmon in appearance"

- Fish Fact from School of Dragons

"The Arctic Char has an elongated body, a small head, and a lower jaw that sticks out."

- Fish Fact in School of Dragons

"The Arctic Char's life span is approximately 20-24 years or more."

- Fish Fact in School of Dragons

Arctic Char (Salvelinus alpinus) are in the same Family as Salmon and Trout (Salmonidae) and have a similar appearance and life cycle. Char spawn in freshwater and live in saltwater.

Atlantic Cod
Cod was first seen in the How to train Your Dragon Movie, when Hiccup brings a downed Toothless fish to eat. Cod are mentioned here and there throughout the TV series, as well.

Though Hiccup refers to the cod in the movie as an "Icelandic" Cod, it is most likely the Atlantic Cod species. This fish is of great commercial value to Scandinavia.

Mulch mentions cod briefly in the first episode of Dragons: Riders of Berk, "How to Start a Dragon Academy". He instructs Bucket to give Hiccup the cod they obtained for Stoick. However, a Terrible Terror stole half of it.

"Hey, we've got some fish for that father of yours. Bucket, give the boy the cod."

- Mulch in "How to Start a Dragon Academy"

Cod are also mentioned in various episodes of Dragons: Race to the Edge.

"Oh, yeah? Well you smell like a barrel of 20-year-old cod livers. That's what drove them away."

- Tuffnut to Ruffnut in "The Zippleback Experience"

"Oh, my Thor! Wasn't he the one who could pass an entire cod through one nostril?"

- Twins mentioning Magmar Thorston in "Reign of Fireworms"

Dagur mentions cod while suggesting a bait for the Thunderfish in "In Plain Sight".

Blindfish
Blindfish can be found in the Whispering Death caves underneath Berk in the game, School of Dragons. This location is not immediately available to the player, but is after completion of the Quest "Explore the Dark Depths". No special rod is required to fish this location.

"The blindfish has sensory papilae on its skin that helps it feel where it is going."

- Fish Fact in School of Dragons

"Blindfish will eat almost anything because food is scarce where they live"

- Fish Fact in School of Dragons

"Blindfish can grow to be four and a half inches long."

- Fish Fact in School of Dragons

The term Blind fish is actually used for any number of fish species that can't see or have under-developed eyes. The fish referred to in School of Dragons is most likely Astyanax jordani, which is native to Mexico.

"Blindfish have no pigmentation, so they look pinkish-white."

- Fish Fact in School of Dragons

"Blindfish have an average lifespan of 2-10 years."

- Fish Fact in School of Dragons

Brown Trout
Brown Trout are freshwater fish seen in the game, School of Dragons fishing activity. They can be caught in most freshwater fishing locations in the game, and are especially abundant in the Wilderness area near Mulch.

"Brown trouts travel from lakes to rivers and streams to spawn."

- Fish Fact in School of Dragons

"Brown trout eggs are concealed in a gravely nest called a redd."

- Fish Fact in School of Dragons

"A female brown trout can lay more than 10,000 eggs!"

- Fish Fact in School of Dragons

"Brown trouts spawn in late autumn. The eggs hatch from the end of April until mid May."

- Fish Fact from School of Dragons

"Brown trouts have high resilience for warmer water than many other types of fish."

- Fish Fact from School of Dragons

Brown Trout (Salmo trutta) are in the same Family as Salmon and Char (Salmonidae) and have a similar shape and life cycle. Native to Europe, these fish have been introduced all over the world in suitable habitats.

"A brown trout is a medium-sized fish. It can weigh up to 20 pounds and can grow longer than 20 inches."

- Fish Fact from School of Dragons

"Most brown trouts have black spots along their dorsal fin, sides and back. A light halo circles each black spot."

- Fish Fact from School of Dragons

"A brown trout feeds on insect larvae, invertebrates, flying insects, and occasionally other fish and frogs."

- Fish Fact in School of Dragons

"Brown trout is mainly a freshwater fish, but it can sometimes live in salt water."

- Fish Fact in School of Dragons

"A brown trout's favored habitats are brooks, lakes, and streams."

- Fish Fact in School of Dragons

Copperband Butterflyfish
A distinctly marked fish appears in the game, School of Dragons, in the underwater portion of the Ship Graveyard (introduced in the "Secret of the Leviathan" Expansion) as well as in the sea adjacent to Vanaheim during the Expansion, "Wrath of Stormheart". It has a white base with yellow stripes running in a dorsal-ventral direction. Best guess identifies it as a Copperband butterflyfish, though the specimen in the game does not have the characteristic thin beak.

Copperband butterfly fish (Chelmon rostratus) are tropical fish found in the Pacific and Indian Oceans in reef ecosystems. They are often kept as pets or for display in saltwater aquariums.

Dolphinfish
In the game, Dragon Training Legends, the player must guide a Scauldron through the sea, avoiding Viking trash and eating tasty fish. Though not specifically named, one such fish appears to be a Dolphinfish. They strangely seem to lack the crest-like dorsal fin that the species is known for, but they otherwise look normal.

Dolphinfish (Coryphaena hippurus), also known as Mahi-Mahi or Dorado, live in temperate to tropical saltwater worldwide.

Eels
See the page Eel (Franchise) for more information.

Flounder
Flounders are mentioned as a metaphor for Ruffnut's hair by Throk, as part of a poem in honor of her, in the Dragons: Race to the Edge, Season 5 episode, "Snuffnut". Flounders are not actually seen in the Franchise.

"A poem for the modern woman. Hair, it smells of flounder. Skin, rough like the coral of a thousand-year-old reef. Lips, dry as jerky made from the giant clam. No hand will be severed from this woman, for she is modern. She is Ruff. She is Nut. She is Ruffnut."

- Throk

Haddock
Though no fish specified as haddock are seen, this fish is most notable in the Franchise as being the last name of Hiccup and his family. Haddock (Melanogrammus aeglefinus) are located in the oceans all around Scandinavia and are in the same family as Cod.

Halibut
Halibut are saltwater fish seen in the game, School of Dragons fishing activity. When fed to dragons, they give 10 energy points to the Dragon.

"Halibuts have very small scales. They cannot be seen because they are enclosed within the skin."

- Fish Fact in School of Dragons

"The female halibut is considerably bigger than the male halibut."

- Fish Fact in School of Dragons

"A female halibut weighing over 250 pounds can produce up to four million eggs."

- Fish Fact in School of Dragons

"A halibut can weight up to 500 pounds or more, and can grow up to 9 feet long."

- Fish Fact in School of Dragons

"A halibut will feed on almost any animal it can fit into its mouth."

- Fish Fact from School of Dragons

Halibut, specifically Atlantic Halibut, are found in the North Atlantic and would have been available to historic Vikings. Halibut is a type of flat fish who lies on its left side and the eyes migrate to the right side of the head as it ages.

"The Halibut is the largest known flat fish, with a body shaped like a diamond."

- Fish Fact in School of Dragons

"Halibuts prefer staying at the bottom of the sea, but will move upwards if the source food is short."

- Fish Fact in School of Dragons

"Halibuts tend to be a dark brownish color on their upper body and white on their underbelly."

- Fish Fact in School of Dragons

"Halibuts are born with an eye on each side of their head. Over time,one eye moves to the other side of the head."

- Fish Fact in School of Dragons

"Female halibuts spawn in the beginning of winter."

- Fish Fact in School of Dragons

Dagur mentions halibut while suggesting a bait for the Thunderfish in "In Plain Sight".

Hawkfish
In the game, Dragon Training Legends, the player must guide a Scauldron through the sea, avoiding Viking trash and eating tasty fish. Though not specifically named, one such fish appears to be a Hawkfish.

Hawkfish are members of the Cirrhitidae Family. All members of this family live in tropical waters and would not have been encountered by historical Vikings. The Hawkfish species that most resembles the variety seen in the game is the Longnose Hawkfish (Oxycirrhites typus). While the real fish is significantly smaller and isn't blue in color, the two both share a long nose and a raised back fin. The Longnose Hawkfish can be found on tropical coral reefs in in the Indian and Pacific Oceans, where it prefers to live around corals near deep-water drop offs. It is well known for being a common aquarium fish. Many Hawkfish species have some sort of reddish coloring on part or all of their bodies, such as the Flame Hawkfish (Neocirrhites armatus).

Herring
Herring are saltwater fish seen in the game, School of Dragons fishing activity. When fed to dragons, they give 5 energy points to the Dragon.

"Herrings spawn at various times throughout the year, depending on the species and the temperature of the water."

- Fish Fact from School of Dragons

"Herring keep their mouth open while swimming, filtering plankton for food."

- Fish Fact in School of Dragons

Schools of herring are also seen in Thornado's exclusive Flight Club lessons, which take the player underwater in a reef setting.

"Herrings have a single dorsal fin with no lateral line, and their dorsal fin is not made of spines."

- Fish Fact in School of Dragons

Herrings are also mentioned in Rise of Berk. Strangely enough, Mulch states that dragons don't like herring, which is the opposite of School of Dragons.

"Herrings communicate through farts."

- Fish Fact in School of Dragons

The Herring encountered by Vikings are the Atlantic Herring (Clupea harengus) and are a very important commercial fish worldwide. Humans have been eating Herring for a few millennia, and is the main ingredient in such foods as "Pickled Herring" and "Kippers".

"During the daytime, herrings swim in the deeper depths to avoid predators"

- Fish Fact in School of Dragons

Ice Tail Pike
While Pike (Genus Esox) are fish occurring in freshwater in real life, the species "Ice Tail Pike" is fictional. It appears to have the body shape of real pike species and is green with light green to white markings.

"It is rare and indigenous to Outcast Island"

- Outcast soldier

The Ice Tail Pike appears in the Dragons: Race to the Edge, Season 5 episode, "Return of Thor Bonecrusher. Some Dragon Hunter bandits kidnap Alvin the Treacherous and ransom him for these fish in order to feed their army of Singetails.

Later, in Dragons: Race to the Edge, Season 6, Ice Tail Pike are seen frequently in a number of episodes, and are implied to be much more widespread than just Outcast Island. They are also said to be the fish that Singetail dragons eat.

Mackerel
"What, ow, you love mackerel!"

- Snotlout to Hookfang in "Total Nightmare" Mackerel are mentioned here and there in the How to Train Your Dragon (Franchise), but seen only once in the Dragons: Race to the Edge, Season 1 episode, "Total Nightmare". The fish seen is not an accurate portrayal of a mackerel, but rather the fairly blunt-headed generic fish seen throughout the Franchise.

The term "Mackerel" is actually used to describe a number of different species. The species that historical Vikings most likely had contact with is the Atlantic Mackerel (Scomber scombrus). These are important food fish that travel in schools near the shores.

Minnow
Minnows can be caught in any Freshwater area in the game School of Dragons, and can also be used as bait to caught other fish. Minnows only give a dragon 1 energy point when fed to them.

"A minnow represents any type of small, silvery fish."

- Fish Fact in School of Dragons

"Minnows are mostly found in freshwater"

- Fish Fact from School of Dragons

In the game, Dragon Training Legends, the player must guide a Scauldron through the sea, avoiding Viking trash and eating tasty fish. Though not specifically named, one such fish appears to be a Minnow.

"Minnows are often raised as food for other fish or as bait to catch larger fish."

- Fish Fact in School of Dragons

"The Minnow's spawning season fall between spring and midsummer."

- Fish Fact in School of Dragons

"Female minnows lay their eggs on or near the bottom of aquatic plants."

- Fish Fact in School of Dragons

The term "minnow" is actually rather generic, referring to any number of small fish species that are not useful to eat but may be used as bait fish and can be fresh or salt water fishes. There is a Family of freshwater fish that are called "true" minnows - the Cyprinidae. Cyprinidae can also be called the "Carp" Family, in which carp and goldfish are also members.

"Minnows consume larvae, crustaceans, and aquatic insects."

- Fish Fact in School of Dragons

"Most species of minnows are under four inches long, but can grow up to a size of fourteen inches."

- Fish Fact in School of Dragons

"Minnows have teeth in their throat to help grind the food they eat."

- Fish Fact in School of Dragons

Northern Wolffish
The Northern Wolffish is a saltwater species seen in the game, School of Dragons fishing activity. They can be fished for in arctic locations in the game, and were introduced to the game at the release of Icestorm Island.

"The Northern Wolffish has razor-sharp teeth to help protect it from predators."

- Fish Fact from School of Dragons

"The Northern Wolffish feeds on crabs, sea urchins, brittle stars, and starfishes."

- Fish Fact in School of Dragons

A deceased Northern Wolffish is also seen prepared to be eaten among a group of other Viking seafood in the book Look And Find: How to Train Your Dragon.

"The Northern Wolffish lives in cold waters below 5 degrees Celsius."

- Fish Fact in School of Dragons

The Northern Wolffish (Anarhichas denticulatus) is native to the colder waters of the North Atlantic. They are predatory fish, feeding on smaller fish and crustaceans, among other things. They are edible, but their flesh is considered "watery" and are not fished commercially. The Wolffish's populations are in decline, however, because of falling victim to bycatch when fishing for other species.

Ozark Cavefish
Ozark Cavefish can be found in the Whispering Death caves underneath Berk in the game, School of Dragons. This location is not immediately available to the player, but is after completion of the Quest "Explore the Dark Depths". No special rod is required to fish this location.

"The Ozark Cavefish is roughly two and a half inches long."

- Fish Fact in School of Dragons

"Ozark cavefish do not have eyes. They have sensory organs on the head and sides."

- Fish Fact in School of Dragons

"The Ozark cavefish eats small crustaceans, salamader larvae, and bat guano."

- Fish Fact in School of Dragons

Ozark Cavefish are native to about 15 caves in middle America in or near the Ozark mountains. Historic Vikings would not have encountered this fish at all. This tiny fish is whitish and translucent. It has only rudimentary eyes but no optic nerve. Instead it has highly developed sensory papillae to navigate its pristine cave waters. It subsists on bat dropping and plant material that end up in the caves such as leaf litter and tree roots.

"The Ozark cavefish is threatened because of pollution, humans, and loss of habitat."

- Fish Fact in School of Dragons

"Ozark cavefish can live in water with extremely low oxygen levels."

- Fish Fact in School of Dragons

"The Ozark cavefish lives in total darkness and is blind."

- Fish Fact in School of Dragons

Paradise Fish
In the game, Dragon Training Legends, the player must guide a Scauldron through the sea, avoiding Viking trash and eating tasty fish. Though not specifically named, one such fish appears to be a Paradise Fish.

Paradise Fish are actually colorful freshwater members of the Gourami Family, Osphronemidae. They can come in striped reds and blues, but purple varieties have not yet been bred. They are often kept as aquarium fish and are native to Eastern Asia. Vikings would not have encountered Paradise Fish in real life.

Perch
Perch are freshwater fish seen in the game, School of Dragons fishing activity. When fed to dragons, they give 5 energy points to the Dragon.

"The perch belong to the Percidae family. It is a freshwater fish."

- Fish Fact in School of Dragons

"A male perch is darker than the female perch."

- Fish Fact in School of Dragons

"A perch has a very strong and long spine."

- Fish Fact from School of Dragons

"Perch breed during the late spring season. They lay eggs onto soft weed beds."

- Fish Fact from School of Dragons

Perch refers to one of three species in the Genus Perca. The species Vikings may have encountered is the European Perch (Perca fluviatilis). They prefer lakes, ponds, and slow-moving rivers, but have moved into brackish water, fast-flowing rivers, and even low-saline sea areas. Perch are popular for anglers to catch, and is even Finland's official national fish.

"Perches feed on crustaceans, aquatic insect larvae, smaller fish, shellfish, and corals."

- Fish Fact from School of Dragons

"A perch has an average size of about 10-20 inches."

- Fish Fact from School of Dragons

"The perch are a colorful breed of fish with a row of spines along the dorsal fin."

- Fish Fact from School of Dragons

"Perch raise their fins to protect themselves when endangered. The spines on the fins are super sharp!"

- Fish Fact from School of Dragons

Powder Blue Tang
Blue fish with a distinctive black face appear in the underwater portion of the Ship Graveyard location in the game, School of Dragons. This area first appeared during the Expansion "Secret of the Leviathan". These fish are conjectured to be Powder Blue Tang, based on their color and markings.

Powder Blue Tang (Acanthurus leucosternon) are tropical oceanic fish occurring in the Indian Ocean around reef areas. Their diet consists mostly of algae. They may be harvested for use in aquariums, but otherwise are not consumed or used for other purposes.

Pufferfish
In the game, Dragon Training Legends, the player must guide a Scauldron through the sea, avoiding Viking trash and eating tasty fish. One of these fish is a Pufferfish. In game, as in real life, they can inflate and deflate, with the Scauldron not being able to eat them while they are inflated and their spikes are up.

Pufferfish are any number of species in the Family Tetraodontidae. They are found mainly in tropical regions, and some species can be found in temperate areas. Pufferfish are known for their ability to "puff" up like a balloon when threatened. They do this by sucking in water (or air if out if the sea) into their extremely flexible stomachs. They additionally have some sort of spikes on their bodies, making it even more difficult for potential predators to grab them. Most species also have some level of tetrodotoxin in their tissues, which is lethal to humans.

Royal Angelfish
A fish appears in the game, School of Dragons, that differs only in color, but strongly resembles in body shape and markings, the Royal Angelfish. Real life Royal Angelfish (Pygoplites diacanthus) are tropical marine fish with bold white strips on a yellow and blue wide body.

The similar fish appears swimming around in the underwater cave area near Stormheart's battle ship, The Tempest, which was introduced during the release of the Expansion, "Rise of Stormheart". Another possible Royal Angelfish is seen in the waters off the coast of Vanaheim in the Expansion "Wrath of Storm Heart".

Salmon
In How to Train Your Dragon, this fish was fed to Toothless during the second time Hiccup met him in the cove. He placed it in a basket before presenting it to Toothless.

"Different species of salmon have different lifespans. They mostly live for 2-8 years."

- Fish Fact in School of Dragons

"Salmons vary in color. Some are red, blue, or silver."

- Fish Fact from School of Dragons

"Grizzly bears often hunt salmons as the fish swim and jump upstream."

- Fish Fact from School of Dragons

Salmon are also seen in the game, School of Dragons, where the player can fish for them in both saltwater and freshwater fishing locations. When fed to a Dragon, the dragon gains 15 energy points.

"The size of a salmon is directly related to how old it is."

- Fish Fact in School of Dragons

"Salmons change in color when they are ready to spawn."

- Fish Fact from School of Dragons

"Salmons can find where they were born by using their sense of smell. They use familiar ocean currents and tides to go back to their birth place."

- Fish Fact in School of Dragons

Salmon is a general term for several species in the Family Salmonidae. Most species occur in the Pacific Ocean and freshwater tributaries to it, but one species, the Atlantic Salmon occurs in the North Atlantic. This is the species Vikings probably encountered. Like most salmon species, the Atlantic Salmon spends most of its adult life in the ocean, then migrated in land to freshwater tributaries to spawn. The fry grow in the freshwater environment, and when old enough travel to the ocean.

"Salmons swim and jump upstream to their original birthplace to lay and fertilize their eggs."

- Fish Fact in School of Dragons

"Salmons can swim several thousand miles to spawn."

- Fish Fact from School of Dragons

Salmon also figure in Norse Mythology. The God Loki transforms into a salmon to escape punishment after he tricked blind Hodr into killing his brother Baldr. The other Gods, however, threw out a net to catch him, and as Loki was jumping over the net as a Salmon, Thor caught him by the tail.

"Young salmons eat plankton, invertebrates, and insects. Adult salmons eat fish, eels, shrimps, and squids."

- Fish Fact in School of Dragons

"When the salmon leaves to enter the stream, it stops eating and only uses stored energy to go on."

- Fish Fact from School of Dragons

Sea Bass
A Sea Bass is seen prepared to eat, heavily salted, by Tuffnut Thorston in the Dragons: Race to the Edge, Season 3 episode, "A Grim Retreat".

The fish pictured is not representative of any sea bass, but rather a generic fish model seen in various shows. In actuality, the term "Sea Bass" is applied to a large number of fish. One species that is sometimes referred to as a sea bass is the European Bass (Dicentrarchus labrax). Its distribution includes coastal waters around the British Isles, Denmark, and the tip of Sweden, so historic Vikings may very well have feasted on this fish.

Shark
See the pages Shark and Hammerhead Shark for more information.

Sturgeon
A deceased sturgeon dressed like Stoick the Vast is briefly seen in "Fright of Passage". Smoked sturgeon is Viking food mentioned by Gobber the Belch in "Frozen". Bucket and Mulch also begin slapping each other with sturgeons when their bludgeons are stolen by Smothering Smokebreaths in "Smoke Gets in Your Eyes". The fish seen is not an accurate portrayal of a sturgeon.

Sturgeons, (Family Acipenseridae) are a group of fish found in both freshwater and saltwater habitats. They are edible fish, but are more widely known in modern times for their caviar. This is one of the great stressors on their populations, as Sturgeons reproduce very slowly. They are long-lived; some species can live for over 100 years.

Tuna
"Hey! Hookfang, you feeling better? Who wants tuna for breakfast? Hookfang? Hookfang?"

- Snotlout in "Total Nightmare" A Tuna was named and seen in the Dragons: Race to the Edge, Season 1 episode, "Total Nightmare". The fish seen is not an accurate portrayal of a tuna fish.

An unnamed fish carried as a tribute to the Red Death appears in the How to Train Your Dragon film. This particular fish looks much more similar in size and body style to that of an actual tuna.

In the game, Dragons: Rise of Berk, the legendary dragon Green Death searches for and retrieves items for the player to use to complete "Collections". One such item is a tuna-like fish. This is most likely a reference to the tribute fish seen in the first Movie.

Tuna are related to Mackerel, and "true" tuna belong in the Genus Thunnus. Tuna species inhabit temperate to tropical waters, so were probably not encountered by historical Vikings.

Viperfish
"Viperfish have many photophores, light producing organs, located along the side of its body."

- Fish Fact from School of Dragons

"Viperfish are known to eat other fish, shrimps, mackerels, and hermit crabs."

- Fish Fact from School of Dragons

Viperfish are saltwater fish seen in the game, School of Dragons fishing activity. In game, the player must fly out to sea on a Gronckle with a special Deep-sea fishing rod to catch these fish. Only Gronckles can be used, because they are able to hover on one place over the sea.

"A viperfish has a huge stomach that can expand up to twice its size. It can use it to stock up on food."

- Fish Fact from School of Dragons

"Viperfish live 5,000 feet below the ocean, but some have been found in shallow waters of 250 feet."

- Fish Fact in School of Dragons

"Viperfish swim at high speeds at their prey and puncture them with sharp teeth."

- Fish Fact in School of Dragons

Viperfish are members of the Genus Chauliodus and live primarily in the deep ocean. They are rarely seen and typically live in temperate or tropical waters, meaning Vikings probably never encountered these fish.

Yellow Tang
In the game, Dragon Training Legends, the player must guide a Scauldron through the sea, avoiding Viking trash and eating tasty fish. While not specifically named, one such fish appears to be a Yellow Tang.

Yellow Tangs (Zebrasoma flavescens) are tropical saltwater fish found in coral reef environments. Historic Vikings would not have encountered these fish. Due to their small size (about 7-8 inches) they have little edible use, but are often seen in freshwater aquariums.

Appearances
The appearances of fish are so numerous across all forms of media that it is not practical to list them all. Below includes an excerpt of appearances, but are by no means all-inclusive.

How to Train Your Dragon (film)
The first ever appearance of fish is in the first movie. The most notable scene is when Hiccup observes the injured Toothless attempting to catch fish from a pond, and then later brings him fish in an attempt to befriend him.

DreamWorks Dragons: Wild Skies
Fish can be gotten by purchasing a fishing rod and fishing for them at various locations. They are then used for luring dragons before training them.

Dragons: Rise of Berk
In this game, dragons help Berk fish. Fish is used for leveling up dragons, clearing trees and forests and upgrading the Wood Stack or Sawmill. Fish are stored in the Fish Basin.

School of Dragons
Fish is used for feeding dragons and in the fishing player activity.

One Farm Job asks the player to harvest corn because "Mulch needs to refill his corn bait supply." As Mulch is a fisherman, he apparently uses corn as fish bait.