Pregnant or not

i ordered the Zulu special I moved him about one or two weeks into the pregnancy but a day later I moved him right back. a week ago his pouch grew a lot in a short period of time(this happened after he was moved) I think he is pregnant acctually I am almost positive he is pregnant,but he should give birth any day now.

Hi, Nigel!

We have discussed whether or not your male Zulu may be pregnant on a few occasions now, sir, and I should explain that when you order a mated pair of seahorses that does not mean that you will receive a male that is pregnant. It simply means that you will receive a male and female of the same species that have pair bonded. As a rule, they are inexperienced pairs that have been paired up for one or more breeding cycles, but that does not mean that the male is already carrying a brood when he is shipped to you, nor does it guarantee that a mated pair will produce offspring immediately after being introduced to the aquarium.

On the contrary, after the rigors of long-distance shipping and the stress of being handled and introduced into a strange new environment, most mated pairs do not reproduce right away. Most often, new arrivals have to go through an adjustment period during which they become accustomed to their new surroundings and their tankmates before they set up housekeeping. As a result, it often takes newcomers several months before they settle down and get serious about breeding and mating. You may have to wait for the right time of year (i.e., breeding season) to roll around and/or for the new arrivals to become comfortable and make themselves at home before they produce any babies.

That’s especially true in your case, Nigel, since you’ve transferred your mated pair of Zulus multiple times since they arrived and experienced problems with ammonia spikes and problems keeping the water temperature in their preferred range. When they were delivered, you first acclimated them into your seahorse tank, which was being treated with copper sulfate, so a short while later you transferred them into your nursery tank instead. Without an active biofilter, the nursery tank experienced ammonia spikes, so you transferred them back to your seahorse tank again a day or two later. Since then you have been struggling to keep the water temperature in your seahorse tank at or below 75°F, and, as you know, heat stress is one of the factors that can prevent Zulu-lulus (Hippocampus capensis) from breeding. All things considered, sir, there is a good chance that your mated pair of Zulus have not bred since you received them and that your male is not pregnant at this time.

However, having said that, anytime you keep a healthy pair of seahorses together under favorable conditions, breeding is pretty much a foregone conclusion at some point. If you provide your Zulus with a nutritious diet, optimal water quality, and a stress-free environment, you can be sure that sooner or later they will produce offspring for you. Keep your water temperature stable between 72°F-75°, and it’s only a matter of time before they mate successfully in your aquarium.

If you want to jumpstart your breeding program, you can indeed order a pregnant male, in which case you’ll receive a gravid male that is carrying young when he arrives. But ordering a pregnant male and ordering a mated pair of seahorses are two different things.

When you do order pregnant males, they are generally in the early stages of pregnancy when they are shipped. That’s because long-distance shipping is too stressful for males that are approaching their delivery date. Unless you actually witness the egg transfer, it takes a week or so for a male who’s carrying a large brood to become noticeably pregnant. So I’d venture to say that most gravid males are shipped out when they are about a week into their pregnancy.

So if you order a pregnant Zulu (Hippocampus capensis), the mail you receive will probably be perhaps 7-10 days pregnant. Gestation times for H. capensis can be anywhere from 14-45 days, with around 21 days being about right at 72°F. But none of that applies in your case, Nigel, if you didn’t specify a pregnant male when you placed your order. If you simply ordered a mated pair of Zulus, chances are your male was not pregnant when he was shipped, and under the circumstances, may not have mated successfully since he arrived.

Best of luck with your Zulu-lulus, Nigel! Here’s hoping they will soon provide you with many broods of healthy newborns!

Respectfully,
Pete Giwojna

Dear Nigel:

Okay, judging from your description of his pouch, it certainly sounds promising! I’m pulling for you, and hoping he is indeed carrying a brood of healthy Zulu babies.

However, a full, enlarged pouch doesn’t always mean that a male is pregnant. 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. Since your male is not having any buoyancy problems or difficulty swimming, Nigel, I think we can probably rule out the third possibility.

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.

Hippocampus abdominalis, H. breviceps, and H. tuberculatus, in particular, have developed enormous pouches that are all out of proportion to their bodies when fully expanded. Their oversized pouches look like over-inflated balloons ready to burst when these stallions come a courting. Take the tiny Hippocampus breviceps, for example. With its brood pouch expanded to the maximum, a courting male looks like a fuzzy 3-inch pipe cleaner that swallowed a golf ball! Courtship in temperate/subtemperate species generally centers around pouch displays more than color changes, dancing or prancing.

Ballooning is much more common in temperate seahorses than tropical species. Thus, male Brazileros (Hippocampus reidi) or male Mustangs and Sunbursts (Hippocampus erectus), for example, are much more likely to engage in a different type of pouch display known as "Pumping" instead.

Pumping requires a series of coordinated movements. 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. Zulu-lulus (H. capensis), like your male, will perform both types of pouch displays when courting, and often concentrate on dancelike displays when flirting with fillies.

During displays of Ballooning and Pumping, the male’s pouch is inflated with seawater, so he maintains neutral buoyancy and can swim normally. As a rule, males don’t perform these pouch displays if they are pregnant. The intrusion of saltwater into the pouch can be harmful to the embryonic young in the early stages of pregnancy because it dilutes or displaces the marsupial fluid that is bathing the fetal fry, and opening the pouch in the later stages of pregnancy is equally disastrous since it may result in the expulsion of pug-nosed preemies still attached to yolk sacs. Ordinarily, once a male seals the aperture of his pouch after the transfer of the eggs, he will not open it again until the hormone isotocin triggers parturition and the birth spasms.

In general, then, it is safe to assume that a male that is performing pouch displays is not pregnant, and it is likewise fair to presume that a gravid male will not indulge in pouch displays. But under captive conditions where flirtatious fillies are always present and sex pheromones from other courting couples may be wafted through the water, just occasionally, a gravid male’s instincts may get the better of him and he may attempt pouch displays regardless of his delicate condition.

Pregnant males do continue to perform the preliminary phases of courtship with their mates. The pair will continue to flirt and dance and brighten in coloration as part of their Daily Greetings, but the male will no longer pump (no pouch displays) and neither the female nor the male will point. The pair will make no more copulatory rises. So a mated pair’s usual morning greeting ritual continues throughout pregnancy, but is limited to the preliminary dancelike courtship displays and normally always stop short of pouch displays. But if a fickle female should begin flirting with another male during her partner’s pregnancy, as commonly happens under captive conditions where monogamy tends to breakdown, it would not be unusual for the pregnant male to intervene and attempt to break up that budding romance.

Close observation of your male over the next several days will hopefully make it clear which of these possibilities is correct in your case, Nigel. Here’s hoping he’s carrying a big brood and will soon present you with a fine new batch of healthy fry.

Yes, all that dancing you observed is a sure sign that your H. reidi have paired up. Hippocampus reidi are famous among seahorse keepers for two things: brilliant colors and making babies. The Brazilian breeding machine is the most prolific of all the seahorses (Abbott 2003). They have a well-deserved reputation for churning out brood after brood every two weeks with relentless regularity, and hold the world record for delivering ~1600 young in a single brood (anecdotal reports of broods up to 2000 fry are not uncommon)! Not bad for a livebearer. But with that many fetal fry crammed into one incubator pouch, the inevitable tradeoff is that the young are born at a considerably smaller size than most seahorses (Abbott 2003). They also go through a lengthy pelagic phase, drifting freely with the plankton for up to 1-2 months, which makes H. reidi fry notoriously difficult to raise (Abbott 2003).

Zulus (Hippocampus capensis) are another prolific species that breed like bunnies in the aquarium when conditions are favorable, so with both your Zulus and your H. reidi are getting serious about breeding now, you are going to be up to your eyeballs in seahorse fry before you know it, Nigel! That’s a nice problem to have and you’ll find the Zulu babies are much easier to raise than the smaller H. reidi fry.

Best of luck with your prolific ponies and all our progeny, Nigel!

Happy Trails!
Pete Giwojna