- This topic has 3 replies, 2 voices, and was last updated 14 years, 9 months ago by Pete Giwojna.
December 24, 2008 at 9:21 am #1582JakeUljansMember
Hi Pete and others,
One of my Asian Emperor seahorses is behaving very strangely. Much of the time he is fine — swimming in the filter jet, scavenging around, eating lots — but periodically he turns quite pale, begins breathing heavily, looking like his head is locked in position close to his body as he swims around quite jerkily in apparent distress. After maybe five minutes of this his colour pattern returns and it seems like business as usual. This has been happening for the last week or so.
I am quite concerned about this development. The other seahorse in the tank displays none of these symptoms. We recently (a couple of weeks ago) had a slight ammonia spike (0.25) but ammonia and nitrates are now normal. Coincident with the ammonia spike was a dramatic drop in pH (down to 7.6 at one point).
The seahorse in question appeared to be losing a little bit of tissue from its back, which I took to be a burn resulting from low pH. This seems to have healed since I have managed to get the pH back up to 7.8 with numerous water changes and regular addition of sodium bicarbonate, although I am yet to get it back to normal. Yesterday I started using a product called eight.four which I hope will get the pH back on track soon.
Have you heard of something like this before, and could it be due to the problematic pH, or is there something else awry?
Many thanks in advance for your assistance, and season\’s greetings!
[Current water parameters:
KH: 12 drops
Temp: 23 degrees C]December 25, 2008 at 2:06 am #4556Pete GiwojnaGuest
Of course, it is terribly difficult to try to diagnose health problems from afar when you cannot see the seahorses or the system they are in, and you have no laboratory tests, cultures, skin smears, wet-mounts, necropsy reports or anything concrete to go on to guide your diagnosis, but my first impression is that the seahorse that has been acting strangely may not be ailing at all.
Rather, it sounds more like your Asian Emperor seahorse (Hippocampus kuda) may be displaying a healthy interest in courtship and mating. It sounds like he may be performing courtship displays in an attempt to entice the other seahorse to mate. The change in coloration you noticed, whereupon the seahorse becomes quite pale, is quite characteristic of courting seahorses. When seahorses are courting, they typically change from their normal dark coloration to a much lighter coloration, which makes them relatively conspicuous and is intended to help them attract a mate. This is known as "Brightening," and is typical of all tropical seahorses. (Tell me, Jake — when the seahorse turns pale, as you describe it, does the face or head of the seahorse retain its normal dark coloration? If so, then it’s very likely that he is merely showing off his courtship coloration rather than developing a sickly pallor.)
Likewise, seahorses perform a number of dancelike displays when they are courting. These include shimmying maneuvers known as "Tilting" and "Reciprocal Quivering," and the seahorses adopt a very distinctive posture when they perform these dance moves during which they keep their heads tucked down. Ordinarily, the seahorses will promenade with their bodies held erect and their heads held high but inclined downwards, so as to keep their chins, errr — their snouts tucked tightly against their necks when they perform these courtship displays (Vincent, 1990). It is normal for the seahorse’s respiration rate to increase when they are courting, or anytime they are excited, for that matter, and when the males perform their vigorous pouch displays for the benefit of the nearby female, it often looks like they are having convulsions or seizures.
In short, Jake, the transitory nature of the unusual symptoms or behaviors you are concerned about makes me think that you may be mistaking flirtatious behaviors and the unorthodox courtship rituals Hippocampus performs as indications of distress. At least, I know of no disease process that would cause the sort of symptoms you report, but only sporadically, for five or 10 minutes at a time, after which the seahorse appears to be perfectly normal and healthy again.
Under the circumstances, I think the best thing you can do is to concentrate on maintaining optimum water quality while you observe the seahorses closely to see if the female eventually responds to the male’s overtures, or conversely, to see if you notice any additional symptoms of a disease problem. In the meantime, be very careful to adjust the pH slowly and gradually. Other than the pH running a little low, your other water quality parameters seemed to be fine. Here is some additional information regarding the water chemistry in a saltwater aquarium so you can see which readings are in the normal range and when you need to be concerned if your readings are off:
Basic Water Quality Parameters.
Natural Seawater Value = 0.010 mg/L
Acceptable Range = 0.000 to 0.050 mg/L
Optimum Level = 0 at all times
Ammonia is highly toxic to both fish and invertebrates in even small amounts (> 0.05 mg/L or ppm). Causes of ammonia toxicity include: immature biofilter (new tank syndrome), impairment of the biological filtration due to antibiotics and other medications, overfeeding, overstocking and dead specimens that go undetected (Webber, 2004). Ammonia levels can also rise after the addition of new animals, after a water change, or following a heavy feeding. Any ammonia level above 0.05 mg/L is a cause for concern, and the source must be found and corrected immediately. Be sure to maintain a good schedule of water changes.
Natural Seawater Value = 0.010 mg/L
Acceptable Range = 0.000 to 0.100 mg/L
Optimum Level = 0 at all times
Nitrite is slightly less poisonous to fishes than ammonia, but deadly to many invertebrates at very small concentrations. Residual levels of nitrite are common in marine aquariums. Levels of 0.05 or less are of little concern in a fish-only aquarium. If the levels are higher than this, the source should be found and corrected immediately. Even trace amounts of nitrite can wreak havoc among the live corals and delicate invertebrates in a reef tank. High levels of nitrite result from the same causes as ammonia.
Natural Seawater Value = 0.050 mg/L
Acceptable Range = 0.000 to 20 mg/L
Optimum Level = below 10 mg/L in fish-only tanks; 0 mg/L in reef tanks.
Nitrate is the end product of the process of nitrification, formed during the Nitrogen Cycle by the oxidation of nitrite by aerobic bacteria. Nitrate is relatively nontoxic to fishes, but elevated levels (> 20 mg/L) are stressful to seahorses over the long term and promote the growth of nuisance algae. Reef invertebrates can be much more sensitive to nitrate, and concentrations as low as 0.06 mg/L can cause problems for symbiotic stony corals. Any level above 5.0 mg/L in reef aquariums is a reason for concern and should be corrected immediately. The nitrate level is a good indicator of water quality and rising levels of nitrates are an indication of deteriorating water quality. For best results, consider using live rock and/or a live sand bed (preferably situated in your sump) in conjunction with a good protein skimmer to help filter your seahorse setup. The skimmer will remove excess organic compounds before they enter the nitrogen cycle, and live rock and a deep sand bed will provide significant denitrification ability, all of which will help keep your nitrates down. Don’t overstock, don’t overfed, remove leftovers promptly (a good cleanup crew is useful here), grow and harvest macroalgae, practice good aquarium maintenance and maintain a sensible schedule for water changes.
Acceptable Range = 8.0 – 8.4 (typically fluctuates between 7.9 at night and 8.4 during the day)
Optimum Level = ~8.2 and stable.
The pH is a measurement of the alkalinity or acidity of aquarium water. A pH of 7 is considered to be "neutral," neither acid or alkaline, while pH levels above 7 are considered to be alkaline or "base," and pH levels below 7 are considered to be acidic. Marine aquaria need to maintain alkaline conditions at all times, and low pH (< 7.6) is especially detrimental to seahorses because it is conducive to Gas Bubble Disease. Normal daily fluctuations in pH are to be expected in the aquarium, and are generally gradual enough not to be stressful (Webber, 2004). Maintaining a sump or refugium with a reverse photoperiod to the main tank can eliminate these natural pH cycles. Regular partial water changes are the key to maintaining stable pH. Buffers can also help but the hobbyist should beware that excessive use of pH buffers may increase KH values to dangerously high levels.
Acceptable Range = 1.020 -1.026
Optimum Level = 1.0245 for most seahorses.
The specific gravity measures the density of a your aquarium water relative to the density of distilled water, and aquarists use it to estimate the salinity of their aquarium water (Trevor-Jones, Dec. 2002). In effect, it’s one way to measure the saltiness of your tank, since the more salt that is dissolved in the water, the denser it becomes. This can also be done by measuring the total amount of dissolved solids in the water, which is expressed as the salinity in parts per thousand (ppt). Hobbyists must remember that constant evaporation of freshwater from the aquarium causes the salts to become more concentrated, which increases the specific gravity or salinity accordingly. Therefore, it is necessary to top off the tank with freshwater regularly in order to make up for evaporation and maintain the desired specific gravity. Seahorses tolerate a wide range of salinity very well and hyposalinity (specific gravity at 1.011-1.015) is often used to help rid them of ectoparasites.
Dissolved Oxygen (02):
Optimum Level = 6 – 7 ppm
High levels of dissolved oxygen are vital to the well being of both fish and invertebrates. The key to maintaining high O2 levels in the aquarium is good circulation combined with surface agitation (Webber, 2004). Wet/dry trickle filters, bio wheels, and protein skimmers facilitate efficient gas exchange and oxygenation. It is important for the hobbyist to monitor the dissolved oxygen levels in the aquarium because a drop in O2 levels is often an early indicator of impending trouble — a precursor of problems ahead. A drop in O2 levels will tip off the alert aquarist and allow corrective measures to be taken, nipping the problem in the bud before it adversely affects his seahorses. Low levels of dissolved oxygen cause lethargy and respiratory distress, and can contribute to a loss of appetite or trigger a hunger strike, in addition to affecting hormone levels and having an adverse impact on a gestating seahorse.
Natural Seawater Value = 2.5 meq/L
Acceptable Range = 2.5 to 5.0 meq/L
Optimum Level = 2.5 milliequivalents per litre (meq/L)is best for fish tanks; > 3.0 meq/L is recommend for reef tanks.
The alkalinity is basically a measure of the capability of your aquarium water to resist changes in pH from the addition of acid (Trevor-Jones, Nov. 2002). Acid is continually entering the aquarium, primarily as the result of respiration (CO2) and metabolic wastes produced by the aquarium inhabitants (Trevor-Jones, Nov. 2002). The addition of these acids tends to lower the pH of the aquarium water. The higher the alkalinity of your aquarium water, the more resistant it is to such downward pH shifts (Trevor-Jones, Nov. 2002). The amount of buffers (primarily carbonate and bicarbonate) in saltwater determines the alkalinity, so the alkalinity in effect is the buffering capacity (Trevor-Jones, Nov. 2002). When the buffering capacity of the water is depleted, the pH becomes unstable. A fluctuating alkalinity will lead to serious problems in
maintaining an appropriate pH, as well as problems keeping calcium and magnesium levels within required ranges. Alkalinity test kits can now warn of low buffering levels in time to prevent potential pH problems (Trevor-Jones, Nov. 2002).
Carbonate Hardness (KH):
Natural Seawater Value = 7 dKH
Optimum Level = 7dKH
Carbonate hardness is another measurement of alkalinity. It is usually expressed in the German unit dKH (degrees of carbonate hardness) and is often considered to be the total alkalinity. (Dividing dKH by 2.8 will give you the alkalinity in meq/L.) KH actually a measurement of various carbonates and bicarbonates of calcium and magnesium within the aquarium water (Webber, 2004). Maintaining a stable KH is very desirable since it maintains the buffering capacity (i.e., alkalinity) of the system and prevents subsequent drops in pH. Aside from stabilizing the pH, reef keepers need to maintain KH and high alkalinity in order to assure that the calcifying organisms in the tank flourish. Corals and other calcifying organisms actively use bicarbonate, which is the main component of alkalinity, so the alkalinity of a tank with a lot of calcification can drop quite rapidly.
Natural Seawater Value = 400 mg/L
Acceptable Range = 350 to 450 mg/L
Optimum Level = 350 – 400 mg/L (up to 500 mg/L in well-stocked reef tanks)
Calcium is a very important element in the water in any marine aquarium and is a vital element in reef tanks. Along with carbonates and bicarbonates, it is required by calcifying organisms such as stony corals, snails and other mollusks, coralline, Halimeda and other calcareous algae, and certain sponges (Trevor-Jones, Apr. 2003). Calcium is a critical parameter for coral growth in reef aquariums, and chronically low levels will cause coral mortality and loss of coralline algae and other invertebrate species. Calcium reserves must therefore be replenished on a regular basis. Regular water changes may achieve this, but reef keepers may require the addition of biologically available calcium to maintain adequate levels (Trevor-Jones, Apr. 2003). Seahorse keepers should be aware that brooding males provide calcium to the developing fry in their pouches, which the embryos probably incorporate into their skeletons. Deficiencies in calcium could thus adversely affect your seahorses’ reproductive success and the health of the fry. In fact, seahorses that receive a diet deficient in calcium often suffer from decalcification of their exoskeleton, a debilitating condition commonly known as “soft plate” disease (Greco, 2004).
Natural Seawater Value = 0.030 mg/L
Acceptable Range = 0.000 to 0.250 mg/L
Optimum Level = 0
High phosphate levels are detrimental to marine aquaria. In fish-only tanks, they promote excessive growth of nuisance algae, such as the dreaded hair algae and red slime algae (cyanobacteria), and in reef tanks they also directly inhibit calcification by corals and coralline algae (Holmes-Farley, 2002). Phosphates arrive in the aquarium in fish foods, through tap water, as an ingredient in low-quality carbon and marine salt mixes, and primarily through the waste products of the inhabitants (Webber, 2004). Avoid overfeeding, maintain a sensible schedule of partial water changes, and use only phosphate-free activated carbon for your aquarium. (Carbon is activated two ways, either with steam or with phosphoric acid. The type of carbon that is activated with phosphoric acid contains phosphates, which can be leached back into the aquarium water and promote the growth of nuisance algae. So you will want to avoid that type of of activated carbon. The carton or box that the activated carbon comes in should be clearly labeled and state specifically that it is "steam activated" or "phosphate free" or something to that effect if it’s a suitable brand for your aquarium.) Growing and harvesting macroalgae and protein skimming are excellent ways to reduce phosphate levels The use of a phosphate absorbing resin is recommended to keep phosphate levels below 0.05 mg/L, if necessary.
Redox Potential or Oxidation Reduction Potential (ORP):
Optimum Level = 350 millivolts
The redox potential relates to the degree of water purity in the aquarium, and can be thought of as a measurement of the water’s ability to cleanse itself via oxidation. It is measured in millivolts of conductivity, a unit that provides information about the reduction and oxidation characteristics of the water. (“Redox” is merely a contraction of reduction-oxidation.) Oxidation-Reduction Potentials (ORP) are closely related to the stability of the marine aquarium and can therefore be used as a barometer of water quality. Highly efficient filtration, good aquarium maintenance and management, and the use of ozone in conjunction with a protein skimmer will help to boost redox values.
Seahorse keepers with fish-only systems need not be overly concerned about many of the parameters mentioned above, but I’ve summarized them anyway for the sake of thoroughness and the benefit of reefers who keep seahorses.
Best of luck with your Asian Emperor seahorses (H. kuda), Jake! Here’s hoping they are merely getting serious about courtship and breeding and that you have nothing to worry about, sir.
Pete GiwojnaDecember 25, 2008 at 6:38 pm #4557JakeUljansGuest
Thank you so much for your helpful and comprehensive reply. From what you have said, it clearly seems that I have simply misinterpreted courtship behaviour. The horse’s head does retain colour and, on a closer look, his pouch is noticeably inflated during the display. That is a great relief. The pH has improved to 8.0 and I will continue to monitor it and gradually bring it up to 8.2
Thanks once again, and a very happy Christmas and new year to you!
JakeDecember 26, 2008 at 2:27 am #4559Pete GiwojnaGuest
Okay, that sounds good. If the head and face of the seahorse retain their normal coloration when the seahorse lightens up or "brightens" in coloration, then he is very likely performing courtship displays for the benefit of the female. If and when the female is receptive towards his advances, you will have an opportunity to witness some fascinating social interactions in the days and weeks ahead, sir.
Researchers have identified and named seven distinct courtship displays seahorses commonly engage in when pairing off to mate, which I have summarized below. These descriptions should give you a better idea of what the mating dance and other courtship displays look like:
2) Tilting, which leads to Reciprocal Quivering
3) Dancing: Carouseling and the Maypole Dance
4) Parallel Promenade
5) Pouch Displays: Pumping and Ballooning
7) Copulatory Rise
Brightening, pouch displays, pointing and rising are seen universally throughout the genus Hippocampus, but there is some variation between tropical and temperate species as well as between dwarf varieties and the larger breeds or greater seahorses. Tropical species tend to exhibit more dramatic color changes during courtship while temperate species often rely more on pouch displays. Dwarf seahorses generally do less dancing and more quivering than the larger breeds, whereas many of the greater seahorses dance their tails off but rarely ever shimmy. Courtship is relatively abbreviated in polygamous seahorses and rather protracted in species that bond strongly, often lasting for a period of 3-4 days during initial pair formation. The terminology researchers use to designate these displays may be unfamiliar at first, but experienced seahorse keepers will immediately recognize the behaviors they describe.
Not every pair of courting seahorses will exhibit all of the displays listed below, but ALL seahorses will demonstrate most of these displays during courtship:
Approaching and Brightening.
This is a very basic display that is seen throughout every phase of courtship. When a seahorse that is ready to mate spots a prospective partner, it will move closer to the other seahorse while maintaining a characteristic posture and signal its intentions by changing in coloration (Vincent, 1990). It will hold its body stiffly erect and brighten up as it approaches (Vincent, 1990). If the other seahorse is uninterested, it will either move away or remain unresponsive, retaining its normal color. But if the other seahorse is receptive and is impressed by what it sees, it will allow the newcomer to move within touching distance and indicate its interest by brightening in return. Either sex may initiate courtship by approaching and brightening this way (Vincent, 1990).
Courtship in the wild is ordinarily conducted in the twilight hours of early morning in the wild. Courting begins with the partners approaching and brightening and ends when they move apart and resume their normal drab coloration again. There will be many such bouts of intense courtship over a period of days during the initial pair formation. Captive-bred seahorses often court more or less constantly and frequently continue courting throughout the day rather than confining themselves to the dawn displays typical of their wild conspecifics. This may simply be a response to a predator-free environment in which it is safe to remain bright and conspicuous regardless of the lighting conditions.
Courtship coloration varies from species to species. However, regardless of the colors involved, the head, dorsal surface (i.e., back), and ventral line (keel) of the seahorse normally remain quite dark while the rest of the body becomes lighter and dramatically intensifies in color (Vincent, 1990). Seahorses flaunt their brilliant coloration in order to impress prospective mates and the overall effect of this change is to make the seahorse much more conspicuous (Giwojna, Mar. 2002
As a general rule, tropical seahorses often undergo more pronounced color changes than temperate species, which tend to be more subdued. Dwarf seahorses (Hippocampus zosterae) are not nearly as bright and flashy during courtship than their bigger brethren. These elfin creatures take on a different sort of glow. They sparkle looking as if they have been sprinkled with glitter, as they take on metallic tints, hues and highlights of their natural neutral colors. Tropical seahorse species generally rely on brightening and conspicuous color changes during courtship more than their temperate counterparts, which depend primarily on pouch displays such as Ballooning.
If all goes well during the approaching and brightening phase, the seahorses usually arrange themselves side by side while facing the same direction. The courtship will then proceed to the next stage with the couple looking their most dashing and debonair.
Reciprocal Quivering and Tilting.
In many seahorses, exchanges of quivering punctuate the next phase of courtship (Vincent, 1990). While perched side-by-side on the same hitching post, the partners adopt a characteristic posture and one of them — usually the male — begins to tremble and quaver. Holding its body stiffly erect with its pectoral fins fully extended, anchored firmly in place by its tail, the quivering begins with the fluttering of the dorsal fin and continues as a shudder that passes down its torso and quickly becomes a rapid sideways vibration of its entire body (Vincent, 1990). After a few moments the male will come to an abrupt halt and the quivering will stop as suddenly as began, only to be resumed by his partner a few seconds later. When the female’s trembling grinds to a halt, the male takes the cue and begins a new round of quivering, picking up where she left off. Back and forth, the seahorses take turns trembling and shuddering, and repeated bouts of these amazing gyrations may be exchanged for several minutes at a time (Vincent, 1990). The couple may entwine their tails during these displays of shimmying.
It’s interesting to note that both the tempo and vigor of the quivering are directly dependent on the size of the seahorses. The sideways shimmy becomes a rapid, high frequency vibration in small species like the dwarf seahorse (Hippocampus zosterae), whereas the movement is much slower in large seahorses like Hippocampus erectus, the lined seahorse. This big, buxom species sways back and forth in a stately, dignified manner. Rather than quivering, males of the larger species often merely “Tilt” towards their partners, a gesture which is akin to a polite, prolonged bow. Reciprocal quivering is an early phase of courtship that is quickly replaced by dancelike displays, but Tilting may still occur right through the final stages of courtship.
Tilting often serves as the warm up or precursor to quivering. Tilting typically begins with the male bowing toward the female and then righting himself again. These repetitive bows increase in frequency, transforming Tilting into full-blown displays of Reciprocal Quivering. The greater seahorses rarely progress past the preliminary Tilting phase, which is the more common of these two complementary performances.
Quivering is the least common of the seahorses’ courtship displays. It is seen much more often — or perhaps is just far more obvious — in dwarf seahorses and the smaller species. The larger breeds often skip over this step and get right down to dirty dancing as the male attempts to herd the female and she circles shyly away from him. Or they may simply Tilt or substitute a little slow motion, simultaneous, side-by-side swaying in place of reciprocal quivering, before busting out the real dance moves.
This delightful display is known as reciprocal quivering for obvious reasons. The male in particular appears to be energized — perhaps “stimulated” is a better description — by this activity. Encouraged by his partner’s enthusiastic response, he will eventually begin to rotate his body toward the female as he quivers. She will move away from him at first, maintaining her space, before returning his quiver (Vincent, 1990). He will then follow after her, attempting to close the distance between them while maintaining his grip on their common holdfast (Vincent, 1990). Quivering soon subsides altogether as she continues to move coyly away and they begin to circle around their hitching post in unison. The next phase of courtship has now begun.
Dancing (Carousel or Maypole).
These are the traditional dancelike displays most people associate with seahorses. They are seen in some form in the majority of seahorse species and dancing dominates the early phases of courtship in the greater seahorses (Vincent, 1990), which do much more of this wondrous underwater waltzing than the dwarf breeds.
Seahorses dance side by side and maintain a typical posture throughout these formal displays. They hold their bodies fully erect with perfect posture, tuck their heads, and conduct themselves with great dignity as they proceed, like ballroom dancers arrayed in tuxedos and formal gowns. The result is a graceful undersea ballet in which the partners grasp a common holdfast with their tails and slowly circle around it in full courtship regalia with all the elegance they can muster (Vincent, 1990). The pair stays in perfect unison as they perform this circling dance in all their finery. Their rigid posture and bright colors irresistibly remind anyone who witnesses this display of the pairs of painted ponies and stately steeds that circle ceaselessly around a merry-go-round at the amusement park. Small wonder then that the researchers who first observed this behavior dubbed it “the Carousel dance.”
Sometimes a pair begins carouseling atop a tall hitching post and spiral slowly downward until they reach the bottom again (Vincent, 1990). This lovely variation of the Carousel dance is known as the Maypole dance for obvious reasons. Together these dances play an integral role in pair formation and daily greetings for most tropical seahorses (Vincent, 1990).
Periodically the prospective partners will interrupt their passionate pas-de-deus long enough to move from one holdfast to another. They do not discontinue their courtship displays when they are on the move, as you might expect. Rather they simply switch from carouseling to a different type of dancing that’s better suited for covering ground. This is a type of highly stylized, side-by-side synchronized swimming known as the Parallel Promenade.
When promenading this way, the graceful movement of the seahorses is best described as prancing. The courting couple maintains precisely the same posture and carry themselves exactly the same way as four-legged horses do when prancing. That is, their bodies are erect with their heads held high, but inclined downwards, so as to keep their chins, errr — their snouts tucked tightly against their necks (Vincent, 1990). The pair swims side by side, facing the same direction, in tight parallel formation as they move from one hitching post to the next (Vincent, 1990). They travel in tandem as if harnessed together as a team. Their tails are often intertwined when they promenade, looking for all the world like a young couple shyly holding hands as they stroll the boardwalk.
Just occasionally, the male Tilts toward the female as they promenade, as if drawn irresistibly toward his partner (Vincent, 1990). If carried far enough, the tilt may become a tremor and then a sideways trembling, and if the female actively cooperates, an impromptu round of reciprocal quivering may result, particularly in miniature species. Eventually the overexcited male will regain his composure, and the promenade will proceed to its intended destination, where more Carousel dancing will ensue.
Like the other dances, promenading is an early stage of courtship seen primarily in large tropical seahorses (Vincent, 1990).
Pumping and Ballooning.
Pumping and Ballooning are pouch display performed to some extent by all male seahorses regardless of species. The energetic display known as "Pumping" is a vital part of the courtship ritual in all seahorse species that have been studied to date. Temperate and tropical seahorses alike, from the smallest pygmy ponies to the largest of the "giant" species, it appears that all male seahorses perform such pouch displays.
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.
Courtship in many temperate and subtemperate seahorses is dominated by such pouch displays. In addition to pumping, these cold-water ponies also engage in a different type of pouch display known as “Ballooning.” This is a simple display in which they inflate their brood pouches 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.
Often all the males in the vicinity will compete for the attention of the same female, chasing after her with their pouches fully inflated this way. When all the boys are in full-blown pursuit of a female ripe with eggs, they look like a flotilla of hot air balloons racing to the finish line.
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.
Pumping is one of the final stages of courtship and it indicates the seahorses are really getting serious (Vincent, 1990). Mating will take place shortly, as soon as the female hydrates her eggs, unless something intervenes in the interim.
Pointing is the prelude to mating and the transfer of the eggs. The female’s eggs will have been fully hydrated by this time, as indicated by the rounded appearance of her obviously swollen abdomen and the protrusion of her oviduct or genital papilla (Vincent, 1990). At this point, she will be anxious, even desperate, to mate. In order to ensure fertilization, the female must add water to her mature oocytes (egg cells) just prior to mating (Vincent, 1990). A ripe female is committed to mating once she has hydrated her clutch of eggs. She cannot retain the hydrated eggs indefinitely (Vincent, 1990). 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. This is an expensive waste of precious bodily resources that must be avoided at all costs. In fact, the whole purpose of the elaborate courtship ritual developed by Hippocampus is to assure that a receptive male is standing by at the crucial moment, ready, willing and eager to accept the eggs.
The ripe female signals her urgency by "Pointing" — rising on the tip of her fully extended tail and stretching vertically towards the surface of the water while raising her upturned head until her snout points straight up (Vincent, 1990). It looks almost as if the female is answering the male’s overtures by nodding her head in assent.
Pointing is an unmistakable sign that the female is ready to rise for the nuptial embrace, which will soon take place in midwater (Vincent, 1990). Pointing thus triggers an immediate response from the male, who typically reacts by Pumping or Tilting (Vincent, 1990). At first there is a stimulus-response relationship between the pointing of the female and the pumping of the male, with one eliciting the other. This helps to coordinate the couple’s courtship, assuring that both partners are fully aroused and physiologically prepared for the transfer of eggs when the moment arrives. There is a direct correlation between the frequency of pointing and pumping and the arousal level of the female and male, and one can easily judge how soon mating will occur by noting the tempo and vigor with which they perform these maneuvers. When mating is imminent, the male often responds not by pumping, but by echoing the female’s Point with one of his own (Vincent, 1990).
If he does not take the hint fast enough, the female will push off the bottom in mid-Point and rise up alone, enticing the male to follow. After a few of these solo rises, the male will eventually get the idea, and prepare to follow her lead. The couple will then rise together for the culmination of their courtship.
This is the final phase of courtship. It is the climax of the entire affair during which the partners meet in midwater for the transfer of the eggs (Vincent, 1990). The female initiates the rise by pushing up from the bottom in mid-Point and the male immediately follows her lead. They ascend through the water column facing each other, with their heads raised high and their abdomens thrust forward (Vincent, 1990). At this point, the female’s genital papillae or oviduct will be everted and protrude slightly from her vent, and the male’s brood pouch is usually fully inflated (Vincent, 1990). As they ascend, the female often continues to Point and the male may continue to Pump (Vincent, 1990). They will meet at the apex of their rise for the nuptial embrace.
The actual transfer of eggs takes place 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 (Vincent, 1990).
As you can imagine, many difficult and delicate maneuvers are required to bring the pair into proper position for this most improbable merging. 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 will separate to rest on the bottom prior to successive attempts. They may require many such rises before the proper positioning is achieved and the crucial connection is finally made.
The female will eventually succeed, with the full and active cooperation of her mate. He positions himself slightly below his mate, with the aperture of his pouch fully dilated and gaping open, ready to receive her eggs. The female will hover directly over the aperture until she can actually insert her oviduct into the opening at the top of his brood pouch or drop her eggs into the basket while hovering directly above the pouch. Pairs occasionally entwine tails when joined, but more often than not their tails will be stretched back behind them, out of the way.
If she makes a good connection, she will extrude her eggs in one long, sticky string, and the pair will hang together in midwater while the transfer is completed, drifting slowly downward as the eggs surge downward deep inside the pouch (Vincent, 1990). The entire clutch — up to 1600 eggs — is transferred in one brief embrace lasting a mere 5-10 seconds (Vincent, 1990). Sperm stream from the male’s urogenital pore into the pouch opening as the eggs are deposited (Vincent, 1990). The couple separates as they descend, drifting slowly toward the substrate. Exhausted by their efforts, the pair seek out comfortable hitching posts for a well-deserved rest. One almost expects to see them light up cigarettes at this point.
The pregnancy-sustaining changes in the male’s pouch begin the moment the last egg is tucked safely away inside this protective pocket. The male’s pouch deflates, compressing the eggs against the pouch lining in order to facilitate implantation. The male then perches and attempts to settle the eggs properly in his pouch, often undergoing a series of agitated contortions, swaying, twitching, or wagging his tail from side to side, and perhaps stretching as though trying to rearrange the eggs more comfortably (Vincent, 1990). He is dispersing the eggs uniformly throughout his pouch, giving each one the best chance to be fertilized and implant in the septum or wall of the marsupium.
Meanwhile, the female’s belly slims down noticeably as she transfers her eggs. She may lose up to 30% of her body weight after depositing a large clutch of eggs (Vincent, 1990). As a result, her abdominal plates or belly rings will be concave or pinched in for the next couple of days.
This charming courtship ritual and delightful displays are a wonder to behold. The grace and beauty of the courtship dance, with its carousel-like ballet and elegant parallel promenade, the rhythmical swaying and passionate performances of "Pointing" and "Pumping," and the fabulous midwater finale all combine to create an unforgettable spectacle that’s unprecedented in all of nature.
Okay, Jake, that’s the quick rundown on the types of ritual behavior and courtship displays that most seahorses exhibit during pair formation.
It’s good to hear that you have your pH back up into the acceptable range. Be very careful when making any additional adjustments — it’s important not to adjust the pH by more than 0.2 daily, and the more gradually it is adjusted, the better.
Just be patient when you are adjusting the pH and don’t add too much of a product designed to raise the pH too soon. Very often your pH won’t budge at all the first several times that you add such a product according to directions. That’s perfectly normal, so don’t be discouraged if your pH stays at 7.8 in initially even though you’ve added several doses of the product you obtained to raise the pH. Don’t be tempted to add more of it or to add it more often than specified in the instructions. The product must first overcome the natural buffering ability of the saltwater in your aquarium before I can change the pH level significantly. It’s like performing a titration — typically, you add several doses and your pH doesn’t budge at all, but then the very next dose you add may change the pH dramatically. Since you never know when that critical point will be reached, remain patient and continue to carefully add more of the product as directed until the pH does start to change, and then adjust it to the desired level as gradually as possible.
Best of luck with your Asian emperor seahorses (Hippocampus erectus), Jake! Here’s hoping that they continue to thrive and want to produce many broods of healthy young for you.
Happy Trails & Happy Holidays!
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