Hexapos is the only water strider to use the “white fen strider” skin and in found in the Dread Wastes. Chances are you’ve flown over this guy without even knowing because he’s one of the handful of Mists of Pandaria pets which are invisible until revealed by a hunter’s Flare. The only way to find Hexapos is to look for his tracks on the ground and drop your flare where you think he’ll show up next, which is usually just a little bit ahead of the most recent footprint.
The problem with Hexapos is the enormous patrol path… he basically takes a leisurely stroll around the entire zone. The map below shows his patrol route and what tracks you should look out for.