Unfortunately, you used to occasionally get lucky -- because it was listed at the same quality of many easy-to-find pets in the game, some players would occasionally sell it on the AH for pennies, not realizing that they'd been one of a very select group of Hyacinth looters. Which is why Blizzard upped the quality -- when people see an epic, whether it be a pet or a sword, they pay attention.
So now, unless you want to pay a ton of money on the AH, the way to get it for yourself is to grind. Grind, grind, and grind. You've got to grind on the Bloodsails down in Booty Bay -- each one of them has a very small chance to drop one.