Okay this information is directly from "The Complete Guide to Dwarf Seahorses in Aquariums" by Alisa Wagner Abbott. It is a long section, but sounds very specific. Here goes...
"If your seahorse is a male and his pouch looks puffy, your seahorse most likely has air bubbles trapped in his pouch. This is probably the most common problem you will run into with dwarf seahorses. It is related to mating rituals and courtship displays, especially if you have equipment that produces air bubbles." (more is explained here about mating rituals...)
"The symptoms of problems with air bubbles or gas bubbles are an enlarged pouch and difficulty swimming due to positive buoyancy. Often the male will float helplessly on the surface, unable to get himself down. Without treatment this will cause a slow and painful death."
"Burping the Pouch
The first attempt or two at performing this procedure can be very intimidating due to the small size of the patient but after you have done it once or twice you will be a seasoned seahorse surgeon, highly skilled in burping pouches. To expel the trapped air, you will hold the seahorse with your non-dominant hand while trying to hold his tail back out of the way with a finger. Once you have him secured, you will need something to insert into the opeing of his pouch. A pouch kit purchased specifically for this purpose is the best, but you can use the coated end of a clean bobby pin or the blunt end of a toothpick or any similar clean object. While securing the seahorse, insert the instrument with steady, even pressure, not too strong-we don't want to puncture the skin-but just firm enough so that the tip of the probe slips into the aperture of his pouch. He will be fighting you every inch of the way, and this is where you will need your third hand to help. Don't have a third hand? neither do I. The first time I had to do this I sure wished I did, but after that scary first attempt, I've found this procedure to be very easy. Nowadays I can do it blindfolded, and I've even become adept at massaging the air out using only one hand."
"After you have inserted the instrument into the pouch, push gently on the sids of the pouch, working from the bottom of the pouch upward to the entrance. If you are doing it correclty, you will see very tiny bubbles escape as you near the top. Push from the bottom upward a few more times until you have expelled all of the air bubbles. If all goes well, the pouch will be completely deflated and he will be able to swim completely normally again. However, if he is still floating after you release him, you will need to burp him again. This is stressful, but seahorses are very forgiving and often will swim away and start eating immediately afterward as though nothing happened."
"Massaging the Pouch
If this procedure sounds too alarming, there is another way of expelling the air that sometimes works and is even less invasive, called pouch massage. You may even wish to try this method first. I do not always have luck with this technique, but if it is successful, it may be easier on both you and your seahorse."
"To perform this method, you hold the seahorse by your non-dominant hand and massage the pouch firmly, yet gently, working upward with a circular motion from the bottom of the tail toward the top. Sometimes with dwarves, just pressing a finger into the middle of the pouch will cause the pouch to open and the bubbles to be released. The bubbles are tiny and may spring out quickly, so pay attention. If either operation - burping or massaging- is successful, it's an instant cure and your seahorse should be back to normal immediately."
There are other things discussed that may be causing this floating noted later in the book but it suggests they usually don't happen to dwarves. I hope it helps, let me know what happens, I would love to know!