I love how everyone always mentions Dragon Dance + Moxie, but i'll give you a brief history of ze past:
During episode 10 and 10.5, Moxie was broken. A Gyarados with Moxie = Gyarados with no ability there.
My Gyarados never had Moxie, it still has Intimidate. And as you know, i'm one of the people that always praised Gyarados. ALWAYS.
And it was during episode 10 that Gyarados saved me the most... yeah...
:I
Also, let me just say that every Water type poke is good, as long as you are nice to it xD