He is. You have to take your time while searching though, he is known to burrow underground and his dot and icon will disappear from the map and UI. What I suggest is getting NPC scan add-on if you don't already have it. It will just simply detect his presence and go off when he is near. Makes him a lot easier to find, along with the other rares. Just make sure you clear your cache after it has him logged if someone else happens to beat you to taming him.
But that add-on is more than worth getting, especially for hunters But if you choose not to get it, simply give it time when swimming around that area. You only have a few seconds (maybe 30?) when he is above the ground...simply enough time to find him and tame him as quickly as possible before he vanishes back into the ground and pops up elsewhere.
So he doesn't stay in one spot then. I was thinking maybe the horse is too fast and that I probably keep missing him. The sea mount travels at 450% speed. Perhaps this doesn't give the game enough time to render him.
Originally Posted by Validity
If rogues become shit, all they can become is a different type of shit.