Eddy,
Looks like you had a good trip. Cozumel offers so much diversity in the dive sites. Many of your pictures are good. You might try to get a little closer to eliminate some of the blue water between you and the subject. Getting lower and shooting on the same level as your subject works better in a lot of cases. It takes patience and waiting out the jawfish, as you did, can be rewarding.
You asked for pointers and suggestions on the photography, but reading thru your blog site, a couple of things really got my attention.
Even though seahorses are a great find and fun to photograph, your safety HAS to come first in all your diving. Preoccupation with the photography can be distracting and you have to be more aware of these issues when you take a camera underwater.
You indicated you knowingly put yourself into deco and even ran out of air during your ascent as a result of staying too long to capture "the perfect" image of a seahorse. In another dive, you became low on air and were near an air sharing situation. Both situations are extremely dangerous. The DAN accident reports are full of incidents where people 'pushed the limits'.
I'm sure you learned a lot from your trip and will be a safer diver in the future.
Sorry to preach, but I couldn't help myself.
Welcome to the world of underwater photography...be safe and have fun