Quote Originally Posted by Abdula
Actually, Isonade has three tails and although the Kyuubi and Orochi are the strongest, the number of tails does not represent their strength.
You're right, Isonade has three tails and three dorsal fins. But the number of tails certainly is indicative of a Kitsune's -- or monster fox's -- strength. A one-tailed kitsune is much weaker than a nine-tailed one. Tail number doesn't reflect strength in general in the folklore, it does in a specific case, and my assumption is that Kishimoto imposed an order against his nine creatures. And like I said, it's just speculation.

But it make sense when you think about Naruto's fight with Gaara. Naruto was able to beat Shukaku with only a tiny bit of the Kyuubi's chakra. He didn't even have to use a "tail" -- or transform into a mini-Kyuubi like he did against Sasuke or Orochimaru.