Bonded Pairs

Dear Harry:

I’m happy to hear that your Mustang stallion is doing so well.

Male seahorses are typically somewhat less active than the females. The stallions tend to be real homebodies that will often choose one particular hitching post as their home base and spend much of there time perched right there (think of your Dad hunkered down in his favorite easy chair in the den). Researchers studying seahorses in the field therefore refer to males as "site-specific" because they can be found at the same tiny patch of reef or seagrass day after day, rarely straying from their chosen spot. Whereas females seahorses roam over a home territory of up to one hundred square meters, the male will spend most all of this time hanging out at his tiny base of operations within his mate’s much larger territory.

As a result, mature males are often naturally more shy and retiring than females, which can be quite brazen at times. I suspect this is due to their parental duties — during the breeding season, pair-bonded males are ordinarily ALWAYS pregnant, and they can’t risk exposing their precious cargo to any more risk than absolutely necessary.) So normally the unfettered females tend to be far more footloose and fancy free, a little more on the frisky side, while the males are often more shy and retiring.

It’s a bit out of the ordinary for your female to be timid and reclusive, but all seahorses have distinctive personalities, for sure, and she may simply be a little more meek in nature than most fillies. Your tank has a thriving pod population, so no doubt she’s been grazing on the natural fodder in your aquarium. That may be why she is spending a lot of time hanging out in the background behind the rockwork — that may be where the hunting is best in your reef since amphipods and copepods like to hide out in the darker nooks and crannies amidst the live rock and coral, right along the substratum.

But we want to encourage your filly to come out in the open, where you can observe her and enjoy her presence, and it’s important that she learns to eat from your feeding station, so I would concentrate on that for now. I would try target feeding her at least once or twice a day, as described below, so that she learns to associate your presence with good food and a full belly. Seahorses are ruled by their stomachs, so once she learns to recognize you as the giver of gourmet delights — the source of her favorite goodies — and is readily accepting frozen Mysis from your baster or feeding wand, it should be an easy matter to lead her out from the background into the open and teach her to eat from your feeder. Before you know it, she’ll be heading for your feeding station as soon a she notices you approaching the aquarium.

Target Feeding

The individual personalities of seahorses naturally extend to their feeding habits. Some are aggressive feeders that will boldly snatch food from your fingers, while some and shy and secretive, feeding only when they think they’re not being observed. Some like to slurp up Mysis while it’s swirling through the water column, and some will only take Mysis off the bottom of the tank. Some are voracious pigs that greedily scarf up everything in sight, and some are slow, deliberate feeders that painstakingly examine every morsel of Mysis before they accept or reject it. Some eat like horses and some eat like birds. So how does the seahorse keeper make sure all his charges are getting enough to eat at mealtime? How does the hobbyist keep the aggressive eaters from scarfing up all the mouth-watering Mysis before the slower feeders get their fair share? And how can you keep active fishes and inverts with seahorses without the faster fishes gobbling up all the goodies before the slowpoke seahorses can grab a mouthful?

Target feeding is the answer. Target feeding just means offering a single piece of Mysis to one particular seahorse, and then watching to see whether or not the ‘horse you targeted actually eats the shrimp. Feeding each of your seahorses in turn that way makes it easy to keep track of exactly how much each of your specimens is eating.

There are many different ways to target feed seahorses. Most methods involve using a long utensil of some sort to wave the Mysis temptingly in front of the chosen seahorse; once you’re sure this has attracted his interest, the Mysis is released so it drifts down enticingly right before the seahorse’s snout. Most of the time, the seahorse will snatch it up as it drifts by or snap it up as soon as it hits the bottom.

A great number of utensils work well for target feeding. I’ve seen hobbyists use everything from chopsticks to extra long tweezers and hemostats or forceps to homemade pipettes fashioned from a length of rigid plastic tubing. As for myself, I prefer handfeeding when I target feed a particular seahorse.

But no doubt the all-time favorite implement for target feeding seahorses is the old-fashioned turkey baster. The old-fashioned ones with the glass barrels work best because the seahorses can see the Mysis inside the baster all the way as it moves down the barrel and out the tip. By exerting just the right amount of pressure on the bulb, great precision is possible when target feeding with a turkey baster. By squeezing and releasing the bulb ever so slightly, a skillful target feeder can keep a piece of Mysis dancing at the very tip of the baster indefinitely, and hold the tempting morsel right in front of the seahorse’s mouth as long as necessary. Or if the seahorse rejects the Mysis the first time it drifts by, a baster makes it easy to deftly suck up the shrimp from the bottom so it can be offered to the target again. In the same way, the baster makes it a simple matter to clean any remaining leftovers after a feeding session. (You’ll quickly discover the feeding tube is also indispensable for tapping away pesky fish and invertebrates that threaten to steal the tempting tidbit before an indecisive seahorse can snatch it up. And it’s great for tapping on the cover to ringing the dinner bell and summon the diners for their gourmet feast!)

In short, target feeding allows the hobbyist to assure that each of his seahorses gets enough to eat without overfeeding or underfeeding the tank. And it makes it possible to keep seahorses in a community tank with more active fishes that would ordinarily out-compete them for food, since the aquarist can personally deliver each mouthful to the seahorses while keeping more aggressive specimens at bay.

The key to keeping active specimens like firefish or cleaner shrimp successfully with seahorses is to feed the other fish and inverts with standard, off-the-shelf aquarium foods first, and once they’ve had their fill, then target feed the seahorses.

In the meantime, Harry, if you want to make sure your female is getting enough to eat, try to get a good look at her cross-section to see if she is losing weight. Compare her girth to that of your Mustang stallion who you would know is eating well. Here’s what to look for:

Basically, you just want to make sure all your seahorses have full bellies at the end of the day, as indicated by their well-rounded abdomens. After a good feeding, the seahorse’s belly rings should be flush or even slightly convex in cross section when viewed from head on. (We never want to see sunken, severely pinched-in abdomens on our seahorses! Concave belly rings are a sure sign of an underfed seahorse, with the sole exception of a female that has just transferred her eggs.)

So if you want to check whether your female is eating well or not, Harry, don’t look at her profile — examine her head-on. Her abdomen or belly plates should bulge out slightly or at least be flush with their flanks, not pinched in or sunken. In other words, when viewed from the back or from head-on, the cross-section of her abdomen should appear concave "( )" or flush "l l" rather than concave ") (" or pinched in.

Best of luck with your new Mustangs, Harry! Here’s hoping you soon have your female eating right from your fingers.

Happy Trails!
Pete Giwojna

Dear Harry:

Male seahorses still compete more actively and aggressively when it comes to pursuing members of the opposite sex, but otherwise, they burden of pregnancy has certainly shifted the sex roles in other aspects of their behavior.

Yes, sir — shy, reclusive behavior is sometimes a sign of a broody male who is carrying young. If you suspect your male may be pregnant, here are some other indications to look for that indicate mating has occurred and that the pregnancy is progressing normally:

Indications of Pregnancy.

If you witness the copulatory rise and exchange of eggs there is no doubt that mating has occurred and, knowing the date of conception, you can confidently begin the countdown toward the maternal male’s delivery date. Knowing approximately how long the gestation period will be allows plenty of time to prepare nursery tanks, set up a battery of brine shrimp hatcheries, and culture rotifers and ‘pods for the insatiable fry.

But what if you missed the big moment? How do you proceed if you missed the actual mating and transfer of eggs, and you’re not sure if you will soon be dealing with a gravid male and hordes of hungry newborns?

There are no aquatic obstetricians, underwater ultrasounds, blood tests or over-the-counter pregnancy tests to perform, and I shudder to think how one might go about collecting a urine specimen to dip! No worries. Fortunately, there are subtle signs and suggestions that indicate a pregnancy is underway. There are number of changes in the parents’ appearance and behavior to look for. For instance, the male and female will still continue to flirt, but the nature a their displays will change from full-blown courtship to regular greeting rituals.

After mating, in subsequent days the couple will continue to change colors and brighten up when in close proximity and dance together in an abbreviated version of courtship known as the Morning Greeting or Daily Greeting. The pair exhibits the same basic behaviors and maneuvers as when they were courting with one big difference — the male never "pumps" and the female does not "point."

In addition, as the pregnancy progresses, the male’s pouch darkens due to the proliferation of epithelial and connective tissue and the placenta-like changes taking place in the wall of the marsupium, and the pouch gradually swells and expands according to the number of young developing within. The latter is not always a reliable indicator, however. Inexperienced couples often spill eggs during the exchange and a male’s first few broods are often inordinately small. The brood pouch of a male that is carrying only a few fetal fry is hardly any larger than normal, and hobbyists have often been surprised by unexpected births under such circumstances.

On the other hand, an experienced male carrying a large brood can be easily distinguished by his obviously expanding pouch. These mature breeders may carry broods numbering over 1600 fetal fry, depending of course on the species. A stallion incubating hundreds of fry will have an enormously distended pouch by the time his due date approaches.

Gravid males often become increasingly reclusive and secretive as their pregnancy advances. When the onset of labor and birth is imminent, the male will begin to shows signs of distress and his respiration rate will increase to 70-80 beats per minute. The fully developed young become very active and shake loose into the lumen of the pouch shortly before delivery. In some cases, the writhing of the young can be detected through the stretched membrane of the pouch, which causes the male considerable discomfort. He may become restless and agitated as a result, swimming slowly to and fro and pacing back and forth like, well — an expectant father. The fry are usually born in the early morning hours between midnight and dawn, arriving all at once or in multiple batches 24 hours apart.

So if you happen to miss the exchange of eggs, watch closely for the following indications that mating has occurred:

(1) A change in the physical appearance of the parents. The gravid male’s pouch will change from a light opaque color to a dark brown due to the elaboration of the internal structures and thickening of the walls of the pouch. It will enlarge steadily over the next few weeks as the young grow and develop, and the aperture will change from fully dilated to a tightly closed vertical slit. The female’s trunk will change from rotund, full with ripe eggs, to noticeably shrunken and pinched in immediately after the exchange of eggs.

(2) A change in the seahorses’ courtship displays. 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.

(3) A change in the behavior of the male. He may become increasingly shy and reclusive. Gravid males may go off their feed as the delivery date approaches, missing meals or even going into hiding. When birth is imminent, he will become agitated and distressed and his respiration will increase markedly.

When you notice these telltale signs of pregnancy, it’s time to kick your brine shrimp hatchery into high gear and start some microalgae and rotifer cultures brewing.

Best of luck with your seahorses, sir!

Happy Trails!
Pete Giwojna