Cobia are smoking fast fish.
I just did a dive off niggerhead reef (hey I didn't name it, from the south side it looks like a dude wearing a big afro) which sits off Palm Beach inlet a little to the north in about 125' of water.
Was hanging out at about 12-15', with about 150' of visability doing some decompressing when a group of cobia went by me at warp speed. Thought something was chasing them as I got out my bang stick but they just turned around came back, took a look and bam they were gone again. Wanted to take one home but they were too smart and way too fast.
We seem to encounter lots of cobia while we're scalloping along the nature coast. 4-8 feet of water and they lazily swim around looking for handouts.