Eel (Franchise)

An Eel is a type of fish usually distinguished by their elongated appearance and small fins. They can live in both fresh water and salt water. There are two species of Eels that live in the waters of the Barbaric Archipelago, the Yellow Smoked Eel lives in waters of Berk and the Bloodvein Eel, which is native to waters of Eel Island. Most dragons hate eels but Typhoomerangs do not.

A list of Eels
Yellow Smoked Eel- The Yellow Smoked Eels are black colored eels with yellow spots or stripes. They are common in the waters of Berk and eel island.

Bloodvein Eel- The Bloodvein Eels are violet colored eels with red spots on their body. They are native to waters of Eel Island. This species of eel is highly aggressive, and are known to attack humans, shown when a bloodvein eel attacked Hiccup and attempted to choke him, along with some other eels.

In the Film
When feeding Toothless in the cove, Hiccup discovered Toothless was afraid of eels. He later used this in dragon training in the Zippleback lesson. He scared the Zippleback (later named Barf and Belch )  back into the cage, leaving the teens and Gobber in shock.

Riders of Berk
Eels have made two appearances in the series. First in the episode  Animal House, they use them to show the animals that dragons are afraid of things too. However, the eels get loose, scaring the dragons and the dragons accidently hurt the animals, mainly a sheep accidently hit against a wall by a Monstrous Nightmare.

Then it made an appearance in the episode The Terrible Twos. In the mentioned episode, they use eels as a new test called the "Eel Reaction Test" on the baby Typhoomerang, only for it to devour the eel, making the Typhoomerang the only known dragon to not be scared of eels.

Defenders of Berk
Eels appear again in the episode, The Eel Effect. In this episode it's discovered that eels can transmit a disease known as eel pox. How humans get it is unknown, but dragons contract it by ingesting an eel. The symptoms of this disease on dragons include erratic behaviour, explosive red fire, an increase on the shot limit, strange eyesight and hearing.Human symptoms are coughing and strange behaviour. The Typhoomerang is immune to this disease though and may conciously ingest eels to increase their shot limit. Eels are also part of the ingredients necesary to build a remedy to the pox.