Ninetales is a fox-like Pokémon that have nine tails, hence its name. Resembling the nine-tailed fox kitsune, they are mainly covered in a light, yellowish-cream-colored fur, while the tips of their nine tails are orange. On top of their head is a large tuft of hair, similar to its pre-evolved form though much more unruly.
Additionally, there are no gender differences between male and female Ninetales. The shiny version of Ninetales has silver-gray fur instead of its usual light cream fur, and its tail is tipped in blue.
All Ninetales have the abilityFlash Fire, which powers up its Fire-type moves if it is hit by a fire-type attack. It also keeps it from getting damaged by fire attacks. This does not apply to Dream World Ninetails, who instead possess the ability Drought, creating a permanent Sunny effect for the duration of the battle or until another weather-altering move or ability is used.
Ninetales' tails are cursed, and pulling one will result in getting cursed.
Ninetales is based on the legendary Kyuubi no Kitsune (九尾の狐 nine-tailed fox) of Japanese folklore. When a Kitsune gains its ninth tail, its fur changes from the dark red of a fox to white or golden, hence the color change for the evolution.
Ninetales are rarely ever male, like Vulpix.
If you put a female Ninetales in the daycare with a male Pokémon that knows Energy Ball, the hatched Vulpix will know Energy ball, despite not being able to learn Energy Ball from TMs.
Ninetales in the Game Boy Advance games didn't have the orange coloring on the tip of its tails.
Ninetales' box sprite does not have the orange coloring on the tips of its tails.
In the Game Boy Advance games, shiny Ninetales' didn't have blue coloring on the tip of its tails, like its normal coloring.
Ninetales was mistakenly misspelled as "Ninetails" for the number of tails it possessed. This misspelling is also on the trading cards.
In the Pokédex, it is said that those who grab one of Ninetales's tails, they get cursed for 1000 years.
In Pokémon Mystery Dungeons Blue and Red, the Gengar was originally a human that grabbed one of Ninetales' tails and was cursed into the form of a Gengar. Also the Gengar, before it turned into Gengar, had abandoned its Gardevoir, but the Gardevoir had no grudge against him, and it loved its trainer enough to protect it from Ninetales' fury.
Ninetales appears to be based on a fox. Its name means nine tails and the Pokémon does actually have nine tails.