Egga a float

Dear hold your horses:

Yes, it is not at all uncommon for an inexperienced pair of seahorses to spill some or all of the eggs during their initial attempt to mate. As you have seen, Hippocampus erectus ova are bright orange ovoids about 1.5 mm in diameter. Unlike most fish eggs, which are round or nearly so, seahorse eggs are pear-shaped. They are full of oil droplets and rich in carotenoids (yellow to red pigments), which help to provide an intracellular source of oxygen for the fetal fry. The presence of these pigments gives the eggs their characteristic orange coloration. The eggs are negatively buoyant and sink to the bottom when released but they are sticky to the touch initially and may therefore cling to seagrass or the branches of a hitching post. They must have been recently released if they are all still in the form of a sticky string.

So it sounds like your seahorses are actively interested in breeding, but that they botched the egg transfer. That’s not unusual with inexperienced pairs that often find coitus awkward and difficult to accomplish successfully.

In order to ensure fertilization, the female must add water to her mature oocytes (egg cells) just prior to mating. A ripe female is committed to mating once she has hydrated her clutch of eggs. She cannot retain the hydrated eggs indefinitely. They can only be retained for approximately 24 hours, before they must be released. She must transfer these eggs to a receptive male within 24 hours of hydration, or lose the entire clutch. Should she be unable to transfer them to a receptive male within that time, she risks becoming egg bound, and her only recourse is to release them into the water column, spilling her eggs onto the substrate.

The actual transfer of eggs takes place at the apex of the copulatory rise while the couple is suspended in midwater or slowly descending toward the bottom — a maneuver that is every bit as tricky as it sounds. Coitus is marked by an extremely awkward, fleeting embrace, aptly described as little more than a brief belly-to-belly bumping.

As you can imagine, many difficult and delicate maneuvers are required to bring the pair into proper position for this most improbable merging, and inexperienced pairs often struggle to get it right. The female will attempt to insert her oviduct into the gaping aperture of the male’s inflated brood pouch. An inexperienced pair will often end up misaligned, perhaps at right angles to one another or with one of the partners too high or too low to join. This is very typical of the many false starts and abortive attempts that are ordinarily involved. The frustrated couple may even separate to rest on the bottom briefly between mating attempts. They may require many such rises before the proper positioning is achieved and the crucial connection is finally made.

So under certain circumstances, it’s not at all unusual for eggs to be spilled while mating or even for a female to drop her entire clutch of eggs, if necessary. As long as your tank is tall enough to allow your seahorses to mate comfortably, you shouldn’t be at all concerned at discovering some dropped eggs. Practice makes perfect, and sooner or later your pair will get it right and begin producing broods with clocklike regularity.

Because males inflate their brood pouches with water to the bursting point during courtship displays aptly known as "Pumping" and "Ballooning," it’s easy to mistake the distended pouch of a courting male for a pouch full of fetal fry and developing embryos. One rule of thumb that can help avoid such confusion is that when a stallion’s pouch remains swollen and distended for more than three days in a row, then and only then is it safe to assume that you’re dealing with a gravid male and a genuine pregnancy, rather than an amorous male performing pouch displays. In the meantime, don’t get too excited about a breeding male with a puffed up pouch, because he may simply be inflating his pouch with water in an attempt to impress the eligible females.

At any rate, the spilled eggs are a sure sign that one or more of your stallions is trying hard to get pregnant and that at least one of the females is receptive and doing her best to oblige him, so if your male is not actually pregnant at the moment, chances are good that he will be before too long. However, a female that has dropped her clutch of eggs normally won’t hydrate more eggs and attempt to mate again until the next breeding cycle, so your pair may have to wait a few more weeks before they try again.

Best of luck with your seahorses, holdyourhorses! Your seahorses are certainly displaying a healthy interest in courtship and mating, so the chances are excellent that they will present you with more offspring before long.

Happy Trails!
Pete Giwojna

Dear hold your horses:

Okay, I’ll be rooting for you and your ponies! Chances are excellent that they will get it right the next time and successfully transfer at least a portion of the eggs.

I would also like to invite you to participate in Ocean Rider’s new training program for seahorse keepers, which will help prepare you for the challenge of raising any babies that may be forthcoming when your pair of seahorses successfully complete the mating ritual. One entire lesson in the training course is devoted to courtship and breeding, and the following lesson is devoted entirely to rearing the young, so the information in the training course may be very useful for you.

This basic training is very informal and completely free of charge. Ocean Rider provides the free training as a service to their customers and any other hobbyists who are interested in learning more about the care and keeping of seahorses. It’s a crash course on seahorse keeping consisting of 10 separate lessons covering the following subjects, and is conducted entirely via e-mail. There is no homework or examinations or anything of that nature — just a lot of good, solid information on seahorses for you to read through and absorb as best you can, at your own speed:

Aquarium care and requirements of seahorses;
Selecting a suitable aquarium for seahorses;
size (tank height and water volume)
filtration
aquarium test kits
Optimizing your aquarium for seahorses;
lighting
water movement and circulation
hitching posts (real and artificial)
aquascaping
substrate
Cycling a new marine aquarium;
The cleanup crew (aquarium janitors & sanitation engineers);
Water Chemistry
optimal parameters
water quality & water changes
aquarium maintenance schedule
Feeding seahorses;
Compatible tank mates for seahorses;
Courtship and breeding;
Rearing the young;
Disease prevention and control;
Hippocampus erectus
natural history
professional rearing protocols
Acclimating Ocean Rider seahorses.

If you are interested, I will be providing you with detailed information on these subjects and answering any questions you may have about the material I present. I will also be recommending seahorse-related articles for you to read and absorb online.

In short, the training course will teach you everything you need to know to keep your seahorses happy and healthy, and it will arm you with the information you need in order to tackle rearing when the big day finally comes.

As an experienced seahorse keeper, I’m sure you’ll breeze right through the lessons, HYH, and complete all 10 lessons by the time any babies arrive. If you would like to give the training program and try, just contact me off list ([email protected]) with your full name and some additional details about your seahorse tank (size and dimensions, filtration and equipment, tank inhabitants, and how long the aquarium has been up and running), which we need for our records, and I will get you started on the first lessons right way.

Best wishes with all your fishes, HYH! Here’s hoping your pair of ponies prove to be very prolific and produce plenty of progeny for you in the months ahead!

Happy Trails!
Pete Giwojna

Dear holdyourhorses:

If I understand you correctly, you witnessed your pair of seahorses attempting to mate unsuccessfully on two occasions during which they were unable to successfully complete the egg transfer, with the result that the females spilled her clutch of eggs on the bottom of the tank. After that, you subsequently witnessed two other mating attempts which were unsuccessful and did not result in a pregnancy, but during which no eggs were spilled. You haven’t seen any new mating attempts recently and you’re wondering if the female may have stopped producing eggs, since none were spilled during the last couple of attempts to breed.

It is true that repeated failures to successfully transfer the eggs will sometimes discourage a pair of seahorses from attempting to breed, but that usually only happens when it is the physical conditions within the seahorse tank that prevent them from mating. The most common reason that this can happen is when the aquarium is simply too shallow to allow the couple to complete the egg transfer during the copulatory rise; when the seahorses cannot swim up high enough to carry out the tricky egg transfer in midwater, they may simply give up trying after a while.

But that doesn’t seem to be a problem in your case. You have a 65-gallon aquarium that is 30-inches tall, which is more than adequate for the seahorses to mate comfortably. And your seahorses have been able to rise up and attempt the egg transfer repeatedly, although thus far they have botched all of their mating attempts. Unless there is something else about your seahorse tank other than a lack of height that is preventing the seahorses from executing the difficult maneuvers required for the egg transfer, such as strong water currents in the upper 1/3 of the aquarium that the seahorses are having trouble overcoming when they rise up to mate, I suspect that your problems are primarily due to an inexperienced pair that have yet to master the copulatory rise and exchange of eggs. When that’s the case and there are no physical barriers that prevent the seahorses from copulating in midwater, I would expect your pair to continue trying until they finally get it right.

Under the circumstances, I think it’s unlikely that your female has stopped producing eggs, holdyourhorses. Females normally only ripen one clutch of eggs each breeding cycle, and for Mustangs and Sunbursts (Hippocampus erectus), a mating cycle is typically about one month or a little less. So if you are pair has attempted to mate recently, they may not try again for several weeks, at which time the females should have another clutch of fully mature eggs ready to go.

Seahorses are fractional spawners and very well adapted for producing clutch after clutch of eggs. Females maintain a spiraling assembly line of developing oocytes (egg cells) at all times, only a portion of which are fully mature and are released at each mating (Vincent, 1990). This differs from the reproductive strategy of most fishes, which are multiple spawners that release all their eggs each time they mate and then start over, maturing an entirely new clutch of eggs from scratch for the next spawning.

The structure of the ovaries is unique to syngnathids. They are paired organs, which join to form a single oviduct (the seahorse’s version of a Fallopian tube) just before the urogential pore (Vincent, 1990). Oocytes spiral out from the center of each ovary, creating a coiled sheet of developing eggs at differing stages of growth (Vincent, 1990). The earliest or primordial eggs arise from the germinal ridge that runs the entire length of the ovary, and lie at the center of the coil from which they spiral out as they develop so that the fully mature eggs are the furthest from the center of rotation (Vincent, 1990). Roughly 20-25% of the outermost eggs in this ovarian assembly line are mature, ready to be discharged during ovulation and deposited with the male (Vincent, 1990). Thus, fully 70-75% of the female’s developing eggs are retained in the ovaries after mating, so a new clutch of eggs will mature relatively quickly and lie in readiness for the next mating cycle.

Seahorse ovaries are always active, busy creating and developing new eggs (oogenesis), forming the yolk (vitellogenesis), and resorbing any mature ova (atresia) leftover after mating or at the end of the breeding season (Vincent, 1990). Eggs in all 4 stages of development can be found in the ovaries throughout the year.

So if your pair of seahorses has not attempted to mate recently, the female’s ovarian assembly line has mature eggs ready and waiting right now and she could hydrate them and mate successfully at any point — today, tomorrow, even right at this moment. But if they did attempt to mate recently, albeit unsuccessfully, it may not be for another month before the female is again receptive, with a full complement of mature eggs ready to be deposited with the male.

Most likely it is just a matter of time before your young pair of seahorses succeeds. Continue to provide them with optimum water quality, a highly nutritious diet, and a stress-free environment, and they soon eventually get it right. Good nutrition is especially important in order to ensure good egg production, since a large proportion of the female’s bodily resources go into producing a clutch of eggs. As an example, a female seahorse may lose over 30% of her weight following a successful egg transfer (or a dropped clutches of eggs). So make sure you keep your male and female well fed and maintain good water quality, and your efforts should be rewarded sooner or later.

Best of luck with your pair of ponies, holdyourhorses! Here’s hoping they produce many broods of healthy young for you in the months and years to come.

Respectfully,
Pete Giwojna