I’m sorry to hear about your stallion’s problems with positive buoyancy. If he seems to be floating up pouch first, the problem is most likely due to a buildup of gas in the seahorse’s marsupium.
Males that are actively breeding or actually pregnant are particularly vulnerable to chronic pouch emphysema and other forms of gas bubble syndrome (GBS), and it is not uncommon for a male that is carrying a brood of young to develop problems with pouch gas and positive buoyancy. When this reaches the point where the affected male is floating at the surface, you have no choice but to release the trapped gas one way or another as soon as possible. Otherwise, the seahorse will be unable to feed and will exhaust itself struggling against the tendency to float, resulting in the build up of lactic acid in its blood and associated changes in blood chemistry (acidosis) that further aggravate its condition.
Pregnancy is naturally a high-risk period for pouch emphysema and pouch gas for a couple of reasons. First of all, breeding males are often especially susceptible to chronic pouch emphysema and GBS in general because of the placenta-like changes that occur in the lining of the pouch during pregnancy. Spongelike, its tissues expand as the capillaries and blood vessels swell and multiply. A film of tissue then forms around each embedded egg, providing it with a separate compartment (alveolus) of its own. The thickening of the wall of the marsupium and elaboration of pouch structures around the implanted eggs result in a dramatic increase in vascularization, and this increased blood supply (hence increased concentration of carbonic anhydrase) transports more dissolved gases to the pouch, increasing the risk of GBS accordingly. The increased blood supply to the marsupium during pregnancy thus makes breeding males increasingly susceptible to the formation of intravascular gas emboli (micronuclei or seed bubbles) at this time.
Secondly, pouch bloat can be caused by gas produced by the decay of embryonic material and the remains of placental tissue or other organic matter (possibly even stillborn young) within the brood pouch, if the male is unable to flush it out and cleanse it properly by pumping water in and out during its pouch displays (Cozzi-Schmarr, per. com.).
I know of a couple of cases in which male seahorses developed pouch emphysema and/or other forms of GBS every time they became pregnant. When they weren’t breeding, they were just fine, but when they were carrying a brood of young, they were invariably plagued with pouch gas and buoyancy problems. Providing the GBS was managed properly (typically by administering Diamox orally via gut-loaded shrimp, in such cases), the affected male may be able to give birth normally and recover fully afterwards.
So it’s possible that this could become a recurring problem for your male whenever he becomes pregnant, Don. If that proves to be the case, I will be happy to help you deal with the situation as it rises. When a gravid male develops problems with pouch gas and positive buoyancy during the course of his pregnancy, I usually recommend performing a needle aspiration to release the trapped gas in a noninvasive manner that make allow the male to carry his brood full term and deliver them normally in due course, as described below:
A needle aspiration is a very straightforward technique that simply involves inserting a hypodermic needle through the side of the pouch, tapping into the pocket(s) of trapped gas or fluid, withdrawing the plunger on the syringe and removing the fluid or gas. If you have never done a needle aspiration before, I know it sounds a bit gruesome, but it is a surprisingly painless procedure for the seahorse and is often easier and less stressful for both the aquarist and the patient than performing pouch flushes or repeatedly massaging the pouch. Not only is a needle aspiration less traumatic, as a rule, but it is also often more effective in removing the trapped gas and relieving the problem. A needle aspiration is easier to perform if you have a helper, since an extra pair of hands is very helpful when you’re ready to withdraw the plunger on the syringe and extract the gas from the encapsulated bubble.
The procedure is accomplished while the seahorse is held under water, just as you would if burping or flushing the pouch, and you grasp the seahorse in the same manner as well.
Prepare the needle and syringe ahead of time by sterilizing the hypodermic. When you are ready, wet your hands first and hold the seahorse upright in the water with your non-dominant hand, allowing his tail to wrap your little finger or ring finger so he has a good grip and feels secure.
While the seahorse is thus restrained, use your dominant hand to insert the needle into the side of the pouch (not the front) so you can tap into the pocket(s) of trapped gas.
Remember, you are not performing a subcutaneous or intramuscular injection, so there is no need to use a shallow angle when penetrating the wall of the pouch. Depress the plunger all the way and then insert the hypodermic laterally, from the side of the pouch rather than the front, at a perpendicular angle to the wall of the pouch. Use a big firm, gentle pressure to penetrate the wall of the pouch.
If you missed the pocket of trapped gas on your first attempt, the hypodermic may also withdraw placental fluid from the marsupium and/or yolk from ova implanted within the lining of the pouch, depending on how far advanced the pregnancy is, but that’s not a problem. Very few, if any, of the fetal fry or embryonic young are affected during a needle aspiration, compared to the alternative which is performing a pouch flush and thoroughly cleaning out his pouch.
If you suspect that your male may be pregnant, Don, then that’s the procedure I would suggest you follow for releasing the gas as build up within his pouch. If you’re confident that he’s not actually pregnant at the moment, then I would suggest inserting a small pipette or catheter into the aperture of his pouch to help you release the trapped gas, and then flushing out the pouch thoroughly with an antibiotic pouch solution.
If you refer to Shorty’s recent post titled "micro bubbles," you will find detailed instructions explaining the treatment options for this problem as well as some of the causes. Please refer to the following link:
One of the methods for flushing out the seahorses pouch described in that discussion should work well for you. When the pouch flush is performed properly, some experts report a 100% cure rate for this type of pouch problem.
Once you have released the trapped gas and restored your male to neutral buoyancy, so that he can swim and perch normally again, the chances are good that he will resume feeding as normal.
Good luck resolving your male’s buoyancy problem, Don!