As I'd mentioned in the previous post about the upcoming Darkmoon Island zone in Patch 4.3, there is going to be a new and exciting aquatic pet — The Sea Pony.
The Sea Pony is a seahorse companion pet that can be obtained by fishing the waters off of Darkmoon Island. El's Anglin' reports that the area can be fished effectively with Fishing skill as low as 75, making this pet available to nearly anyone willing to put in the time it takes to catch it. El mentioned having caught this pet after more than 700 casts, with one person on WoWHead claiming as few as 166 casts, so expect that it will take awhile to catch this cute little companion.
Here's a video preview by syigamer of this new Sea Pony pet, along with a glimpse of the new Darkmoon Island wharf area.
Sea Pony Video Preview
The Sea Pony also serves as a preview for what the Purple Puffer will be like. I imagine it will share the same summoning animation, as well as water globe appearance. Both pets are going to be very popular, I'm sure!