Dear Lisa & Andrew:
You’re very welcome!
Okay, it sounds like you are able to release a small amount of gas from your stallion’s pouch, but that this only partially relieved the problem with positive buoyancy. Any air you were unable to evacuate from the pouch was not released within the seahorse’s body instead. The anatomy of the pouch rules this out — there is no opening or connection between the marsupium and the abdominal cavity of the seahorse or between the marsupium and the seahorse’s tail. Allow me to explain in a little more detail:
The brood pouch is the marsupium in which male seahorses incubate the eggs and protect the developing young. The brood pouch is far more than a simple sack or protective pocket or a mere incubator for the eggs. It can rightfully be considered an external womb, which undergoes placenta-like changes throughout the pregnancy.
The marsupium consists of four tissue layers forming an enclosed pouch located under the abdomen on the front of the tail (Vincent, 1990). This structure is found in males only and is strictly external to the body (Vincent, 1990). In other words, it is not contained within the body cavity (coelom) and it is not an extension of the abdomen or the tail. So you needn’t worry that any gas within the brood pouch might have been transferred to the abdomen or the tail of the seahorse when you performed the pouch massage and attempted to burp the pouch.
However, it’s quite possible for a seahorse to have more than one type of gas bubble syndrome (GBS) at the same time. So your seahorse could have a problem with tail bubbles or subcutaneous emphysema in addition to a problem with pouch gas.
Gas bubble syndrome is believed to be caused by gas emboli forming within the tissue of heavily vascularized portions of the seahorse’s anatomy — the placenta-like brood pouch of males, the eye, the muscular prehensile tail — and it can take several different forms depending on where the bubbles or emboli occur. When it occurs in the brood pouch of the male, chronic pouch emphysema or bloated pouch results, leading to positive buoyancy, which is by far the most common form of GBS. When it occurs in the capillary network behind the eye (choroid rete), Exopthalmus or Popeye results, and the eye(s) can become enormously swollen. When it affects the capillary network of the gas bladder (the rete mirabile), hyperinflation of the swimbladder occurs, resulting in positive buoyancy. When it affects the tail or snout, external gas bubbles (i.e., subcutaneous emphysema) form just beneath the skin and look like raised blisters, which is the second most common form of GBS. When intravascular emboli occur deep within the tissue and occlude blood flow, generalized edema results in the affected area. Or extravascular emboli may cause gas to build up within the coelom, often resulting in positive buoyancy and swelling or bloating of the abdominal cavity (internal GBS).
The prehensile tail of the seahorse is often affected when conditions are favorable for the formation of such gas emboli because it has a rich blood supply via the dorsal aorta and caudal vein and because the tail is the site where seahorses tend to store their limited fat reserves (the extravascular seed nuclei or emboli that trigger GBS form most readily in adipose tissue due to the higher solubility of certain gases in lipids than in aqueous tissues). Intravascular bubbles are seen in both the arterial and venous circulation, but with vastly greater numbers detected in venous flows (venous gas emboli). The far more numerous venous bubbles are believed to first form in lipid tissues draining the veins. Lipid tissue sites possess very few nerve endings, possibly masking critical insults at first, and veins, which are thinner than arteries, appear more susceptible to extravascular gas penetration.
Different parts of the body can thus be affected depending on how the
initial gas emboli or micronuclei form, grow and spread. During an
episode of GBS, bubbles may initially form in the blood
(intravascular) or outside the blood (extravascular). Either way,
once formed, a number of different critical insults are possible.
Intravascular bubbles may stop in closed circulatory vessels and
induce ischemia, blood sludging, edema, chemistry degradations, or
mechanical nerve deformation. Circulating gas emboli may occlude the
arterial flow or leave the circulation to lodge in tissue cites as
extravasular bubbles. Extravascular bubbles may remain locally in
tissue sites, assimilating gas by diffusion from adjacent
supersaturated tissue and growing until a nerve ending is deformed or
circulation in nearby capillaries and vessels is restricted. Or,
extravascular bubbles might enter the arterial or venous flows, at
which point they become intravascular bubbles. Extravascular bubbles
can thus become intravascular bubbles, and vice versa, via diffusion
and perfusion. This is important because it means that under certain
conditions extravascular seed bubbles or micronuclei can enter the
bloodstream and migrate from their birth site to other critical areas
as intravascular bubbles. If untreated, the gas bubbles worsen and
the condition is fatal.
In seahorses, oxygenated blood is delivered to the tail via the dorsal aorta, a major artery running the length of the body below the spine, and CO2-laden water is returned via the caudal vein which runs along the inside of the tail. In seahorses, venous bubbles often form at the most distal portion of the tail where the oxygen tension is lowest.
You mentioned that you think most of the remaining gas may be trapped in the seahorse’s tail because there is a little pouch at the base of the tail that appears to be filled with air. What you are describing could be one of the blisterlike subcutaneous emphysema or tail bubbles which characterize external GBS. If that’s the case, Lisa, and your stallion has one or more tail bubbles in addition to his pouch gas, treating him with Diamox is definitely your best option. Tail bubbles or subcutaneous emphysema respond very well when treated with Diamox, which is the only way to treat them successfully aside from compression at depth or in a hyperbaric chamber or a homemade decompression chamber.
However, if the "little pouch at the base of the tail" that seems to be filled with gas is actually the lower portion of your stallion’s brood pouch, which still has air trapped in it, then a needle aspiration would be the best way to remove the gas from the little pouch.
In either case, both chronic pouch emphysema and tail bubbles can be treated very effectively using the Diamox. Unfortunately, obtaining Diamox (the tablet form of acetazolamide) can often be a Catch-22 situation for hobbyists. It is a carbonic anhydrase inhibitor — a prescription drug often used for treating glaucoma, hydrocephaly, epilepsy, congestive heart failure, and altitude sickness in humans, so you have to get it from your Vet or perhaps your family doctor. Unfortunately, Veterinarians are often unfamiliar with Diamox — it’s very much a people med and unless you find a Vet that works with fish regularly, he or she will probably never have heard of gas bubble disease or treating it with carbonic anhydrase inhibitors. Many pet owners are on very good terms with their Vets, who are accustomed to prescribing medications for animals, so it’s often best to approach your Vet first about obtaining Diamox despite the fact they may never have heard of it until you brought it to their attention. Your family doctor, of course, will be familiar with such medications and have Diamox on hand but it can sometimes be difficult to get your MD to jump that final hurdle and prescribe it for a pet. Either way, it can be tough to get the medication you need under these circumstances.
However, I would exhaust those possibilities first before I considered an online source for the Diamox. Print out some of the detailed information that’s been posted regarding pouch emphysema and gas bubble syndrome (GBS) on this forum, and how it’s treated using Diamox, and present that to your family veterinarian and/or your family practitioner. Bring photographs of your stallion and be prepared to bring the seahorse in for a visit, if necessary. (Veterinarians are prohibited by law from prescribing medications to treat an animal they have not personally seen and examined. If you have had a close personal relationship with your vet over a period of years, they are often willing to bend that rule in the case of fish, but you may well have to bring the affected seahorse in for a quick checkup to get the desired results.)
If not — if neither your Vet or family physician will prescribe Diamox — then there are places you can order Diamox online without a prescription, but save that for a last resort. (You can’t always be certain of the quality of the medications you receive from such sources; in some cases, you even need to be concerned about counterfeit drugs, although Diamox certainly shouldn’t fall into that category.) The medications will take a week or two to arrive, which is troublesome when your seahorse is ailing and needs help ASAP. And, as you know, customs officials can confiscate such shipments, although that very rarely happens with this particular medication.
If you ultimately need to go that route, Lisa, the following source is the one most seahorse keepers have found works best:
Click here: Inhouse Drugstore Diamox – online information
They offer 100 tablets of Diamox (250 mg) for around $20 US, but they ship from Canada by mail, which usually takes a little under two weeks for delivery.
The gestation period for Mustangs and Sunbursts (Hippocampus erectus) is typical between 14-30 days, with the average being about 3 weeks. It is difficult to be much more precise than that because gestation in seahorses can be influenced by a number of factors. For instance, it is largely determined by water temperature, is controlled by the levels of key hormones, and can be influenced to a lesser degree by diet and nutrition. In other words, it’s quite possible that your stallion could still be pregnant after three weeks. But it’s also possible that he was never actually pregnant and that the pumping you observed was a courtship display intended to stimulate the female to mate. There’s no way of knowing for sure at this point.
At any rate, all things considered, treating your seahorse with Diamox administered orally and/or performing a needle aspiration are still probably your best options for resolving this problem completely. I know it would take you a while to obtain the Diamox, but it would be prudent to do so and is a very useful medication for any seahorse keeper to have on hand.
In the meantime, if you can refresh my memory regarding the current inhabitants of your seahorse tank, there are a couple of other things I can suggest that may be helpful and could provide your stallions with some relief, so please let me know what sort of cleaners and invertebrates are in the seahorse tank.
Best of luck relieving the positive buoyancy and restoring your stallion to normal again, Lisa and Andrew!