Glowing Algae, also called Flightmare Algae, is a bioluminescent organism that appears in the How to Train Your Dragon franchise. To avoid confusion, it is classified as "flora" (or plant) here.


Glowing algae is seen in multiple occasions in DreamWorks Dragons in the How to Train Your Dragon franchise and is a fictitious organism based in real life.

In the franchise, glowing algae is able to survive in both freshwater and saltwater as it typically flows through rivers and occasionally or eventually flows out to sea. It glows bright blue and appears as droplets of glowing blue blobs when separated from the water. It also appears to be sticky, as it was able to stick to the side of a ship as well as sticking to Ruffnut's and Tuffnut's faces for a while.

When glowing algae is first seen in the franchise in "Fright of Passage", Hiccup hypothesizes that its glow was a reaction to "Aurvandil's Fire" (the Northern Lights), which appears every ten years on Berk, along with the Flightmare. However, the algae seems to glow under its own abilities in the episode, "Maces and Talons, Part 1," which disproves the theory.

Glowing dinoflagellates

Comparison between glowing algae and sea sparkle; from top-left to bottom-right: stream of glowing algae, bloom of sea sparkle, glowing algae with loss of water, packed sea sparkle.

It is possible that the glowing algae is somewhat based on bioluminescent micro-organisms called dinoflagellates, specifically Noctiluca scintillans more commonly known as "sea sparkle". The sea sparkle's bluish glow is a result of a chemical reaction when they are "disturbed", so it is not continuously glowing as the glowing algae appears to be. Sea sparkle can be found mostly along coastlines around the world, so it is possible historic Vikings did come across this organism. There are many other Genera and species of bioluminescent "algae" or dinoflagellates, but sea sparkle is the most notable.


In the How to Train Your Dragon franchise, glowing algae is most noted as a food source for the Flightmare, and appears to contribute to this dragon's bluish glow. It has also been demonstrated that if dragons other than Flightmares eat glowing algae, that the glowing effect is also imparted to them, but in colors possibly roughly corresponding with their hide color. The Flightmare follows a trail of the algae throughout the ocean.


Dragons: Defenders of Berk

In the episode, "Fright of Passage", Astrid Hofferson awaited the arrival of the Flightmare, which tarnished her family's name by causing Fearless Finn Hofferson to freeze with fear. Later, Astrid and Hiccup discovered that the Flightmare can breathe a paralyzing mist, and that this dragon is appearing on Berk because it follows its food source: glowing algae.

Dragons: Race to the Edge

Season 2

Glowing algae is seen again in the episode, "Maces and Talons, Part 1" when Viggo Grimborn and the Dragon Riders clashed at an unnamed island. Viggo was attempting to capture a Flightmare, while the Dragon Riders attempt to stop it from crossing paths with the Dragon Hunter. The Flightmare is attracted to this island because it has glowing algae.


School of Dragons

In the Quest called "Gobber's Wheels of Misfortune", the player must collect glowing algae from behind the waterfall on Berk to bring to the school alchemist, Heather. Heather wants to use it to create a way to view the cracks in metal.

Four different colors of glowing algae (blue, yellow, red, and green) were added for a limited period of time in the shop as part of the 2018 Dreadfall update. They can be fed to the dragons and make them glow in the respective colors for a short amount of time: four hours for small bottles and twelve hours for large bottles. They can be applied to all dragon species in the game, with the Light Fury being the only exception. Still, Toothless can only glow when fed blue algae, possibly because it was the color he was glowing in the episode, "Fright of Passage".

Dragons: Rise of Berk

Flightmare algae (possibly another name for glowing algae) is mentioned is a few dragon descriptions. According to the official description of Sweetcicle, there is a sweet variety of the algae, which only blooms in the spring. It contains high sugar concentrations, which make dragons hyperactive.


  • The glowing algae seems to have a strong effect on the Flightmare's shot limit. According to Dragonpedia, the Flightmare has a shot limit of 4, which is significantly low and inaccurate, when the Flightmare produced a long trail of its toxic mist to surround the Dragon Riders in "Maces and Talons, Part 1".
    • It is impossible for the Flightmare's original shot limit to be 4 for it to produce such a long trail of its mist without any signs of regeneration.
      • The only explainable reason is that the glowing algae has another side effect that increases the shot limit of the Flightmare, or even the toxicity in the mist, since they are both the same color and is somewhat "sticky" as the Flightmare's mist can create a "shiny" aspect on its paralyzed victim.
  • The glowing algae stream was described to be filled with tiny fish in the Dragon Tracker.[1]
    • These fish could possibly be where all the Flightmare's nutrients come from, and the glowing algae instead may just be a side effect and benefit to this diet.



Wikipedia-logo-v2.svg Noctiluca scintillans on Wikipedia

Glowing Algae uses Creative Commons Licensed content from the Dreamworks School of Dragons Wiki page Stable Missions. The list of authors can be found on the page revision history (view authors). SODWikiLogo

Site Navigation

Community content is available under CC-BY-SA unless otherwise noted.