There are three possibilities when a male’s pouch is obviously very swollen and enlarged:
1) He is pregnant and carrying a large brood of developing young;
2) He is courting and performing pouch displays known as “Pumping” and “Ballooning;”
3) He is ailing and his pouch is filled with gas or swollen with accumulated fluid.
When the brood pouch is bloated with gas, we would certainly expect the male to be experiencing positive buoyancy and having severe difficulty swimming, if not actually floating and bobbing at the surface like a cork. On the other hand, if his brood pouch was distended with accumulated fluid (ascites), he would be very likely to have difficulty swimming due to negative buoyancy. When that happens, the seahorse tends to hang downward from his hitching post, rather than assuming the normal upright posture, and he may spend periods of time lying prone on the bottom. If your male is not having any buoyancy problems or difficulty swimming, I think we can probably rule out those possibilities…
It’s also possible that your stallion’s pouch appears bloated because he is performing pouch displays, as explained below in more detail.
Ballooning is a simple display in which courting males inflate their brood pouches with water to the fullest possible extent and parade around in front of the female in all their glory as though trying to impress her with the sheer dimensions of their pouches. The pumped up paramours perform proudly, putting on quite a show for the flirtatious fillies.
Pumping is a similar pouch display that requires a series of coordinated movements and a lot more exertion on the part of the courting stallion. Bending vigorously, the aroused male jackknifes his tail to meet his trunk, thereby compressing his inflated brood pouch in the middle. The male then straightens up again, suddenly snapping back to “attention” so as to relieve the pressure on his severely compressed midsection. This rapid pumping motion has the effect of forcing water in and out of the brood pouch in a manner that is virtually identical to the way the young are expelled at birth (Vincent, 1990).
The strenuous pumping action is the stallion’s way of demonstrating his pouch is empty of eggs and that he is a strong, healthy, vigorous specimen capable of carrying countless eggs (Vincent, 1990). By so doing, he assures the female that he is ready, willing, and able to mate, and that he can successfully carry and deliver her entire brood. The male’s marsupium also becomes grossly distended during displays of Pumping, but in that case, it is obvious the male is courting because it looks like he’s doing abdominal crunches as the vigorously pumps water in and out of his brood pouch. Once a male is pregnant, he seals the aperture of his pouch and no longer performs these displays of pumping, although he will continue to engage in other forms of courtship with his partner during their daily greetings.
During displays of Ballooning and Pumping, the male’s pouch is inflated with seawater, so he maintains neutral buoyancy and can swim normally.
Close observation of your male over the next few days should make it clear which of these possibilities is correct in your case, dkblilie.
Normally, the pouch displays of pumping and ballooning are not maintained for any length of time, if your male’s pouch remains swollen and engorged for more than three or four days consecutively, that greatly increases the odds that you are dealing with a pregnancy and not one of the other possibilities we have been discussing.
Please contact me off list with a brief message at the following e-mail address if your stallion starts having buoyancy problems or shows any other symptoms that indicate that he is not merely performing pouch displays or is perhaps already pregnant, and I will advise you how to handle the problem and restoring to normal again:
Good luck and be sure to keep me informed.
Pete Giwojna, Ocean Rider Tech Support