J.R.R. Tolkien was inspired by an Old English bestiary, appearing in the Exeter Book. The idea of giant marine turtles ultimately derives from Eastern myths, and in the European versions the monster is often confused with whales.
 Other version of the legendarium
It is never explained whether the turtle-fish was an actual race or just a fictional character for the poem "Fastitocalon". In an earlier version of the legendarium, Ulmo, Lord of the Waters, uses his giant whale, Uin, to drag Tol Eressëa towards Aman. This whale reappears in J.R.R. Tolkien's story Roverandom. It is thinkable that Tolkien, in an early phase of the mythology, imagined the fastitocalon to be another one of Ulmo's creatures.
 Portrayal in adaptations
1982-2007: Middle-earth Role Playing:
- Turtle-fish, also called Fell Turtles and Festitycelyn, are described as monsters that can grow as large as fifty feet in length, and that live both in the seas and in the large rivers and lakes.
1995-1997: Middle-earth Collectible Card Game:
- The card "Fell Turtle", released in the set METW, is a Hazard Creature.
2007: The Lord of the Rings Online:
- Dread-turtles, huge reptiles with spiky shells, are possibly inspired by the Turtle-fish. The largest dread-turtle, found in Rohan, is referred to as the Fastitocalon.
- ↑ 1.0 1.1 J.R.R. Tolkien, The Adventures of Tom Bombadil, "Fastitocalon"
- ↑ 2.0 2.1 J.R.R. Tolkien; Humphrey Carpenter, Christopher Tolkien (eds.), The Letters of J.R.R. Tolkien, Letter 255, (dated 5 March 1964); see also "Letter to Eileen Elgar (5 March 1964)" (letter)
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), The Book of Lost Tales Part One
- ↑ Ruth Sochard Pitt, Jeff O'Hare, Peter C. Fenlon, Jr. (1994), Creatures of Middle-earth (2nd edition) (#2012)
- ↑ Randy Maxwell (1997), The Northern Waste (#2025)
- ↑ Jeff McKeage (1984), Hillmen of the Trollshaws (#8040)
|Legendary Races of Arda|
|Animals:||Dumbledors · Gorcrows · Hummerhorns · Pards · Swans of Gorbelgod · Turtle-fish|
|Dragon-kind:||Great glow-worms · Sea-serpents · Spark-dragons · Were-worms|
|Evil Races:||Ettens · Giants · Gongs · Half-trolls · Hobgoblins · Ogres · Snow-trolls · Two-headed Trolls|
|Fairies and Sprites:||Dryads · Leprechauns/Leprawns · Mermaids · Sylphs · White cow|
|Other:||Badger-folk · Great beasts · Lintips · Mewlips · Nameless Things · Spectres|
|Individuals:||The Hunter · Lonely Troll · Man in the Moon · The Rider · River-woman · Tarlang · Tim|