Advice needed

Dear Elina:

I agree with Leslie – those H. capensis are awfully lucky to have landed with such a conscientious hobbyist, especially one with a new 100-gallon tank all ready to receive them! Your aquarium parameters look great, the tank has excellent height for seahorses, and most importantly of all, a temperature of 71-degrees F is suitable for captive-bred Cape seahorses.

It sounds like you’ve done a wonderful job of rehabilitating the H. capensis you rescued thus far, but you will need to address the pouch-gas problem eventually, and in my experience, the sooner you tend to it, the better the outcome is likely to be. It was probably a wise decision to postpone treatment while you were rejuvenating the stressed out ponies, but now that they have settled in and are eating well, I would address the matter promptly.

Since the pea-sized gas bubble has been stable since you’ve had the seahorses, there’s a good chance that simply evacuating the trapped gas can resolve the problem at this point. But if you wait much longer, the stress and exertion of struggling against positive buoyancy and a constantly shifting center of gravity may itself result in chronic pouch emphysema (PE). Allow me to explain in more detail.

Initially there’s no way to differentiate between a simple case of pouch bloat, which is easily cured simply by evacuating the air from the pouch, or pouch emphysema (PE), which is a chronic form of gas bubble syndrome (GBS). The diagnosis of chronic pouch emphysema (i.e., GBS) is made if the problem keeps recurring after the gas is emptied from the pouch.

First I’ll outline the treatment protocol I recommend in cases like this, Elina, and then I’ll explain some of the ways to evacuate the air from your male’s pouch:

First Treatment: Manually Evacuating Gas from the Pouch

At the first sign of a bloated pouch accompanied by any indications of positive buoyancy, the pouch should be "burped" or the trapped gas should be evacuated using a fine catheter. That will provide the affected seahorse with immediate relief, and if this simple first-aid measure resolves the issue, all is well and good.

In that case, the problem was no doubt due to simple pouch bloat, a harmless sort of gas build up that is entirely unrelated to chronic pouch emphysema. Pouch bloat can be caused by gas produced by the decay of embryonic material and the remains of placental tissue or other organic matter (possibly even stillborn young) within the brood pouch, if the male is unable to flush it out and cleanse it properly by pumping water in and out during its pouch displays (Cozzi-Schmarr, per. com.). And in some isolated cases, it’s possible that a bacterial infection of the pouch may also be involved (Cozzi-Schmarr, 2003). But it is far more common for pouch bloat to result from air bubbles trapped in the pouch during courtship displays, especially if the male chooses to display in the bubble stream produced by an airstone or bubble wand or bubble curtain (Strawn, 1954)..

However, hobbyists should be aware that even a case of simple pouch bloat could contribute to recurring pouch emphysema, a much more serious problem, if it is not handled properly. The simple act of struggling against the positive buoyancy that results from pouch bloat can alter the seahorse’s blood chemistry, and result in full-blown PE via acidosis of the blood if the problem is not relieved promptly.

The first indication of both pouch bloat and PE is a loss of equilibrium. The seahorse’s center of gravity shifts as the gas accumulates in its pouch, and it will have increasing difficulty swimming and maintaining its normal posture, especially if it encounters any current. It will become apparent that the seahorse has to work hard to stay submerged, as it is forced to abandon its usual upright swimming posture and swim with its body tilted forward or even horizontally in order to use its dorsal fin to counteract the tendency to rise.

The uncharacteristically hard work it must do while swimming means the hard-pressed seahorse builds up an oxygen debt in its muscles, and the lactic acid that builds up as a result of anaerobic metabolism further disrupts its blood chemistry and worsens the situation. It will struggle mightily in a losing battle against its increasing buoyancy until finally it can no longer swim at all, bobbing helplessly at the surface like a cork whenever it releases its grip on its hitching post. At this point, its pouch will be obviously swollen and bloated.

It is imperative that the gas be evacuated and neutral buoyancy restored long before that happens in order to assure that the affected seahorse is subjected to the least possible stress and does not have to overexert itself for an extended period. The longer it must fight against positive buoyancy, the greater the chances its blood will be acidified in the process and the more likely it becomes that a case of basic pouch bloat can progress into recurring pouch emphysema.

Breeding males are often especially susceptible to chronic pouch emphysema and GBS in general because of the placenta-like changes that occur in the lining of the pouch during pregnancy. Spongelike, its tissues expand as the capillaries and blood vessels swell and multiply. A film of tissue then forms around each embedded egg, providing it with a separate compartment (alveolus) of its own. The thickening of the wall of the marsupium and elaboration of pouch structures around the implanted eggs result in a dramatic increase in vascularization, and this increased blood supply (hence increased concentration of carbonic anhydrase) transports more dissolved gases to the pouch, increasing the risk of GBS accordingly.

Ideally, the air should be evacuated from the male’s pouch at the first sign of positive buoyancy. If this simple procedure does not cure the problem, then it is appropriate to move on to stronger measures once the problem recurs, as described below.

Second Treatment: Flushing the Pouch combined with administering Acetazolamide orally.

In my experience, acetazolamide (brand name Diamox) is much more effective in treating PE when it is ingested rather than administered as a pouch flush or a series of baths. Therefore, if pouch gas recurs a second time, I recommend treating it more aggressively with antibiotic/antifungal pouch washes while feeding the affected seahorse Diamox-injected shrimp (or Diamox bioencapsulated in live shrimp, depending on how badly handicapped the buoyant male happens to be when it comes to feeding).

The pouch flush solution I prefer is a combination of nifurpirinol and neomycin sulfate, since that combo works together synergistically to forms a wide spectrum antibiotic with potent antifungal as well as antibacterial properties (Basleer, 2000). Nifurpirinol (Furanase) and neomycin sulfate (Neosulfex) are the active ingredients in two different commercial products designed for aquarium use, and both of them used to be readily available at your local fish store. Neosulfex has since been discontinued, I believe, but neomycin sulfate is still found in many aquarium medications. If you cannot obtain neomycin, you can substitute kanamycin sulfate instead. Like neomycin, kanamycin is an aminoglycoside antibiotic that can be combined safely with nifurpirinol to form a potent synergistic combination of antibacterials that also have powerful antifungal properties.

Because it is so difficult to distinguish chronic pouch emphysema (PE) from ordinary pouch bloat, which has virtually identical symptoms, many seahorse keepers delay treatment too long when their prize ponies are experiencing buoyancy problems. They will often continue to evacuate the air from the pouch repeatedly in the forlorn hope that their stallion has not developed a life-threatening form of GBS but merely trapped a little air during his pouch displays. Very often this is wishful thinking, which only delays the inevitable and subjects the seahorse to ongoing stress needlessly, while making successful treatment more difficult by increasing the risk that gas emboli will form elsewhere and cause more damage in the meantime. In many cases, all you accomplish by waiting and hoping for the best is to allow the PE to become more advanced, more entrenched, and more severe in the interim.

To avoid this sort of needless delay, I suggest flushing the pouch thoroughly with antibiotics at the first sign of pouch gas and positive buoyancy should your initial attempt to evacuate the air fail to cure the problem (Garrick-Maidment, pers. com.). The affected seahorse must be handled in order to "burp" its pouch or evacuate the air via pouch massage anyway, so I recommend administering an antibiotic pouch wash at the same time.

Not only is repeatedly evacuating the air from the male’s pouch counterproductive in most cases, the constant manipulation can be hard on the tissue of the pouch, aggravating the dermal layers of the marsupium and leaving them vulnerable to secondary infections. (The male marsupium is far more complex than most hobbyists realize, consisting of four separate layers of epithelial and connective tissue, with the innermost layers being heavily vascularized.)

The skin or integument of the pouch is of course its first line of defense against disease. It contains mucus glands, and the slime covering the skin acts as a barrier to ectoparasites and infection. The protective slime may even contain antibodies and antibacterial substances (Evans, 1998). Marine fish are always in danger of dehydration because the seawater they live in is saltier than their blood and internal body fluids (Kollman, 1998). As a result, they are constantly losing water by diffusion through their gills and the surface of their skin, as well as in their urine (Kollman, 1998). The mucus layer also acts as a barrier against this, waterproofing the skin and reducing the amount of water that can diffuse through its surface (Kollman, 1998).

Repeatedly burping or massaging the pouch removes this protective barrier, and the shearing pressures that are involved may aggravate the underlying tissue, resulting in secondary infections of the outer marsupium that can further complicate the picture.

Progressing directly to flushing the pouch plus oral Diamox after the first pouch evacuation helps minimize these repeated insults to the delicate marsupium.

Third Treatment:

If all goes well, as it usually does when the proper measures are performed in a timely fashion, a third round of treatments is normally not necessary. In fact, some experts report a 100% cure rate for pouch emphysema when such pouch flushes are properly administered during the early stages of the condition (Garrick-Maidment, per. com.).

However, if the pouch flushes and an oral Diamox should fail to resolve the problem, the recompression-decompression cure would be your next recourse. Paul Groves found pressurization to be an effective cure for pouch emphysema, as well as the other forms of GBS, while he was conducting his extensive series of trials with gas bubble syndrome.

(In your case, Elina, with an aquarium 25-inches deep, confining the male at the bottom of the tank in a critter keeper, as Leslie suggested, may be all that’s required for this. Hippocampus capensis is a fairly small species and a water depth of 25 inches amounts to 5-6 times the total length of the seahorse, which may just create enough of a change in hydrostatic pressure to pressurize or recompress the seahorse effectively.)

And if they happen to have the necessary equipment already on hand, some hobbyists prefer to treat PE with recompression-decompression as their second form of treatment, skipping over the Diamox and pouch flushes altogether. I have not tried the latter personally, however.

OK, Elina, here are some instructions on how to carry out that first treatment to evacuate the air from your male’s pouch. That should provide him with some immediate relief and hopefully no other treatments will be necessary.

Pouch Massage: Burping the Pouch

Pouch bloat is ordinarily easily resolved by evacuating the gas from the marsupium. This procedure is commonly known as pouch massage or "burping" the pouch and it provides immediate relief for the seahorse when successful. The first attempt or two at performing this procedure can be very intimidating, I know, but it is actually much easier than it sounds.

To expel the trapped air, wet your hands first and hold the seahorse upright in the water with your non-dominant hand, allowing his tail to wrap your little finger or ring finger so he has a good grip and feels secure (Burns, 2001). While the seahorse is thus restrained, use your dominant hand to massage the pouch firmly yet gently between your index finger and thumb, working upward with a circular motion from the bottom of the tail toward the top so as to work the trapped gas upwards toward the opening of the pouch (Burns, 2001). Don’t squeeze the pouch too forcibly, just maintain gentle pressure from below as you massage the pouch, always working from the base of the pouch toward the orifice at the top with your thumb and index finger to force the gas upward.

Hopefully, as your massage moves to the upper half of the pouch and approaches the top, the aperture of the pouch will begin to gape open, allowing a stream of bubbles to escape (Burns, 2001). This is the "burp" you’ve been hoping to produce, and when it happens, you can actually feel the bloated pouch slowly deflate as you gently force the bubbles out (Burns, 2001).

If that does not happen, however, you will have to modify your gas evacuation technique somewhat, this time using the thumb and index finger of your non-dominant hand to massage the pouch with a gentle back and forth motion, while you use a bobby pin or similar blunt implement in your dominant hand to carefully tease open the aperture of the pouch (Burns, 2001).

You are not trying to insert the bobby pin into the pouch at all (Burns, 2001). The idea is to use the rubber-coated end of the pin to gently manipulate the orifice of the pouch, using a sideways pressure on the mouth of the pouch to tease it open, rather than using a downward pressure to force the bobby pin into the opening (Burns, 2001).

Begin as before, holding the seahorse upright in the water with your non-dominant hand, allowing his tail to wrap your little finger or ring finger so he has a good grip and feels secure, while leaving your thumb and index finger free to perform the massage (Burns, 2001). Begin at the base of the pouch near the tail, and massage the pouch gently but firmly between your thumb and index finger, working upwards with a back and forth motion as though gently squeezing a toothpaste tube from the bottom to the top (Burns, 2001).
Meanwhile, using your dominant hand, position one of rubber coated ends of the booby pin at the mouth of the slitlike aperture, and use sideways pressure to prise the lips of the pouch open without actually inserting the pin into the pouch (Burns, 2001). This may take a surprising amount of pressure, so proceed gently but firmly, making sure you direct the brunt of the pressure sideways rather than downward (Burns, 2001). As your massage progresses to the upward portion of the pouch, a few small bubbles at a time will be expelled, and you can feel the pouch gradually deflate between your fingers.

Continue applying pressure from the bottom of the pouch up while prizing the mouth of the pouch open until the pouch feels flaccid and no more gas escapes (Burns, 2001). You may have to repeat this procedure two or three times to be sure you have evacuated all of the trapped gas (Burns, 2001).

If successful, it’s an instant cure and your seahorse should be back to normal immediately, able to swim freely and feed as usual. Burping the pouch is stressful, but seahorses are very forgiving and often will swim away and start eating immediately afterward as though nothing happened. This type of pouch gas is not a serious problem and poses no threat to the seahorse’s long-term health.

Eyedropper Pouch Evacuations

Rather than burping or massaging the pouch, some hobbyists find it easier to use an ordinary eyedropper to evacuate the air from a large seahorse’s pouch. This technique is fairly self-explanatory. Get a glass eyedropper (the smaller the better) from your drugstore — the glass kind that has a rubber bulb. The glass tip is much smoother than plastic droppers are and the rubber squeeze-bulb allows you to apply suction using the eyedropper with one hand while holding the seahorse with your other hand.

Take the seahorse in your nondominant hand, keeping it underwater, of course, and let it wrap its tail round your baby finger. Then take the eyedropper in your dominant hand, squeeze the rubber bulb and hold the bulb squeezed closed while you very gently insert the glass tip into the aperture of the pouch. Once you are just slightly inside the pouch, slowly release the squeeze bulb and the bubbles of trapped air will often be aspirated.

Remove the eyedropper, expel the bubbles it extracted, and repeat the whole procedure as necessary to remove all the trapped air and restore neutral buoyancy. This method of evacuating gas works best with large seahorses.

If you have a Pouch Kit from Ocean Rider, the flushing apparatus can be used in a similar manner to aspirate the trapped air.

Needle Aspirations.

It is also very practical to aspirate air from a bloated pouch using a small hypodermic needle and a syringe. The pouch can easily be penetrated from side and is not harmed by the entrance of the needle. It causes the seahorse surprisingly little discomfort and is often less traumatic that massaging the pouch and other methods for evacuating gas. It is a quick and effective technique and is often easier on the seahorse keeper and his patient than other approaches.

Whatever method you decide to use to evacuate the male’s pouch, be sure to observe the following precautions when manipulating seahorses:

Handling Seahorses

I do not like to use an aquarium net to transfer or manipulate seahorses, since their delicate fins and snouts can become entangled in the netting all too easily. I much prefer to transfer the seahorses by hand. Simply wet your hand and fingers (to avoid removing any of the seahorse’s protective slime coat) and scoop the seahorses in your hand. Allow them to curl their tail around your fingers and carefully cup their bodies in your hand to support them while you lift them out of the water. When you gently immerse your hand in the destination tank, the seahorse will release its grip and swim away as though nothing out of the ordinary has happened.

Composed of solid muscle and endowed with extraordinary skeletal support, the prehensile tail is amazingly strong. Indeed, large specimens have a grip like an anaconda, and when a 12-inch ingens or abdominalis wraps its tail around your hand and tightens its hold, its vise-like grip is powerful enough to leave you counting your fingers afterwards!

In fact, it can be quite difficult to remove an attached seahorse from its holdfast without injuring it in the process. Never attempt to forcibly detach a seahorse from its hitching post! When it feels threatened, it’s instinct is to clamp down and hold on all the tighter. When you must dislodge a seahorse from its resting place for any reason, it’s best to use the tickle technique instead. Gently tickling the underside of the tail where it’s wrapped around the object will usually induce the seahorse to release its grip (Abbott, 2003). They don’t seem to like that at all, and will quickly let go to move away to another spot. Once they are swimming, they are easy to handle.

Best of luck treating your male’s buoyancy problem, Elina! Let me know if completely evacuated the air from his pouch resolves the problem or if his buoyancy problems come back. If the problem recurs, it may be necessary to treat him with Diamox and pouch washes in the next step, or to recompress him at depth.

Respectfully,
Pete Giwojna

Dear Elina:

You’re very welcome! Congratulations on performing a successful air evacuation! That’s a tricky maneuver and it’s always awkward and intimidating the first time you do it. But you seem to have done a fine job and no doubt your male capensis is feeling much better now. Providing the gas build up and problems with positive buoyancy don’t recur, he should be good as new. Eating well and actively courting are a couple of very good signs to that effect.

As for the growling while you were burping his pouch, that’s a very interesting subject. Seahorses are capable of making noises both in and out of water. All seahorse keepers are familiar with the "snick!" they make when slurping up prey, but they will also sometimes emit a series of staccato clicks or high-pitched squeaks when foraging or when held out of the water (Discovery of Sound in the Sea, 2004). What purpose these noises serve or whether they are a form of communication is unknown.

Hippocampus erectus in particular is well known for its ability to "vocalize." Seahorses produce sounds by two different mechanisms — drumming (vibrating their air bladders) and stridulation (scraping the back of the neuroskull against the bones of the coronet). Snicking is produced by stridulation whereas the growling or croaking you noticed is an example of drumming. You were able to feel the growling because the vibration of the air bladder is transmitted to the surrounding tissues and into the water through its body, as we’ll discuss in more detail below.

Marie Fish conducted a study of the significance of sound production in seahorses at the Narragansett Marine Laboratory, University of Rhode Island in 1953 (Bellomy, 1969, p190). She used a hydrophone to monitor and record the sounds produced by a large female northern seahorse (Hippocampus erectus) over a period of several months. She found that spontaneous sound production was limited to first two days in a new environment (Fish, 1953). The seahorse would cruise the length of the tank one or more times in an exploratory manner and then anchor itself to a holdfast and emit a burst of sounds (Fish, 1953). These consisted of sharp clicks in bursts of 2-5 with each snap spaced about one second apart (Fish, 1953). She would then repeat this behavior every 1/2 to 3/4 of an hour for the first day or two (Fish, 1953). After the second day she would fall silent, making no more sounds despite attempts by the experimenters to elicit them. However, each time she was transferred to a new tank, she would resume the same exploring/sound-making behavior for the first day or two (Fish, 1953).

Fish concluded, "…for this one fish at least, sound may be used in new surroundings for orientation, perhaps to find the whereabouts of others of its species (Bellomy, 1969, p190)." Fish notes that the female had spawned recently (Fish, 1953); it may have been searching for its mate. These findings beg the question of whether seahorses are able to locate one another in the ocean using sound. That would certainly be a useful ability for cryptic animals with very patchy distribution and very limited swimming ability.

Interestingly, there are several reports that mating in some seahorse species is often accompanied by clicking and snapping sounds, but I have never witnessed this first hand. For example, in 1970 Fish and Mowbray reported that Hippocampus erectus emitted a high-frequency clicking during courtship, which became louder and almost continuous during the actual mating.

These reports are intriguing because vocalizations in many other fishes are known to play an important role in intraspecific communication, including courtship and territorial behavior (Evans, 1998). There are several mechanisms by which fishes, including seahorses, are known to produce sound. For example, some fishes use their swim bladders as resonance chambers to produce sounds (drumming), using muscles on or near the gas bladder to vibrate the gas-filled membrane. Jorge Gomezjurado has found that Hippocampus ingens can make a "croaking" sound using their air bladder this way (Mann 1998). However, sounds made by drumming are low frequency, ranging from approximately 75 to 150 Hz, so that is definitely not the mechanism seahorses use to generate clicking noises during courtship and mating (Evans, 1998). Instead, the seahorse’s high-frequency clicking is thought to be produced by stridulation, which is simply rubbing or scrapping two parts of the body together to make noise (Evans, 1998). (Crickets, for example, produce their characteristic chirping via stridulation.) Sounds made by stridulating are usually concentrated at the higher frequencies, ranging from approximately 3,000 to 8,000 Hz (Evans, 1998).

Marie Fish identified the bones she believes produce the stridulation. She found "…a loose articulation between the posterior margin of the skull and the anterior margin of the coronet, which is a star-shaped ossified crest mounted in a socket like base. When the seahorse’s head was extended moderately, the articulating bony edges could be seen to rub together, but when elevated more sharply, the coronet overlapped the other bone. Dissection showed adequate muscular equipment to permit such movement in the living fish. It is suggested therefore that the ‘finger-snapping sound’ results when the skull edge slips forcibly under the coronet, or, more likely perhaps, when it snaps out. Vibrations thus set up may be transferred to and amplified by the air bladder (Bellomy, 1969, p190)." In other words, seahorses use friction between the back of the neuroskull and the coronet bone (Mann 1998) to produce high frequency sounds via stridulation.

During the mating embrace, both male and female seahorses are thus said to produce high-frequency clicking sounds by scraping or "snapping" the bony edges on two parts of their skulls together (Discovery of Sound in the Sea, 2004). I should hasten to point out that these presumed courtship noises are distinctly different than the usual "snick" that seahorses make when feeding. They are not associated with eating and the clicks are made in bursts consisting of several snaps in quick succession (Fish 1953).

Although I have never been able to personally verify that seahorses use sound as part of their mating ritual, there is no doubt that the ”good vibes” seahorses give off during their displays of reciprocal quivering play an important role in courtship. The seahorses can certainly detect the vibrations produced their partners during these bouts of side-by-side quivering, and the stimulation this provides may be important in heightening arousal and advancing the courtship toward eventual mating.

Unfortunately, Elina, Ocean Rider does not ship livestock overseas. However, they are happy to provide supplies and dry goods (e.g., Vibrance, pouch kits, etc.) to overseas hobbyists, including Europe and Germany, of course.

As of now, my new book is still unavailable and it could be some time before it’s finally released. I know, I know — it was originally scheduled to be released last January and it’s already long overdue — but right now the matter is out of my hands…

The problem is that TFH just changed publishers several months ago and that has delayed everything. All of their production schedules have been pushed way back as a result. Christopher Reggio, the new publisher at TFH, is both brand new to the company and unfamiliar with seahorses. He therefore wants to defer any action on my book until he’s had a chance to get a better feel for how things work at TFH and has had a chance to further assess the market for an ambitious book on seahorses. He plans to "revisit" my book project sometime early next year and decide the best way to handle it then, after he’s up to speed.

At the moment, Christopher Reggio’s impression is that seahorses are very much a specialty market, and his concern is that that market may simply be too limited to support a major book about seahorses. That’s why he wants to conduct additional market research before he commits to the project, and that’s why TFH keeps talking about coming out with a condensed version of the book first. The abbreviated version of the book would be a trial run to test the market, if it sold well, then TFH would have no qualms about releasing the full-length addition of the book. At any rate, right now all that’s up in the air pending further research…

But don’t worry — one way or another, I will see that the book comes out in its entirety as soon as possible. The moment I have a firm release date, I’ll be sure to let you guys know. And I promise you it will be well worth the wait! In the meantime, you can always reach me online for help with your seahorse-related problems.

Best of luck with your Cape seahorses (H. capensis), Elina!

Happy Trails!
Pete Giwojna