The Water Strider family is the last of the six new for MoP.They as the Quilen are exotic pets ,so they are available only for BM hunters. In the information from the beta servers show two tipes of Water Striders. I'm not still sure which one of them is the right one so I'll show them both and let you decide.
The Water Strider are Cunning pets and their main use is going to be in PVP. But if you look at their passive ability you can see that those pets can be useful in PVE.The passive ability is called Still Water-Infuses all party and raid members within vision with still water, increasing their spell power by 10% and their critical strike chance by 5%. As you can see this spell can be use for big boost in the DPS of any raid. The other unique ability is called Surface Trot-Allows the Hunter and the Water Strider to walk across water for 10 min. Any damage will cancel the effect. For me Surface Trot can be very effective in outdoor PVP.
Water Strider eat fruit and fungus.
I think that with those new pet families Blizzard are trying to make the imagination of the players the key factor about using the pets in PVP or PVE.
So this was my last post about the new pet families in Mists of Pandaria. I hope that you fish them useful and I hope that soon there will be more information.
For final some Water Strider pictures: