I’m very sorry to hear about the problem you are having with your bloated female. Since your female is not having any buoyancy problems, I suspect her trouble is most likely due to either egg binding or constipation, Barbara. (Bloating could also be due to internal gas bubble disease, which would result in positive buoyancy, or abdominal dropsy resulting from a buildup of fluid within the abdominal cavity, which typically results in negative buoyancy or the tendency to sink.) In this case, if the seahorse is still producing normal fecal pellets then you can rule out constipation and the most likely cause of her problem is egg binding, via a processable limitation. Diamox (the tablet form of acetazolamide) is not helpful for egg binding or constipation, but there are other first aid measures you might consider, as discussed below.
This is what I usually recommend in cases like this, Barbara:
When the abdomen of a female seahorse is obviously swollen and bloated and she is reluctant to release their grip on her hitching post, there are several possibilities to consider:
(1) she may have become egg bound;
(2) she may have become constipated;
(3) she may have developed internal gas bubble disease, in which case her abdomen is swollen with gas and she will be experiencing problems with positive buoyancy;
(4) she may have developed ascites (abdominal dropsy), in which case her abdomen is told with fluid and she will be experiencing problems with negative buoyancy.
Let’s examine each of those possibilities in a little more detail.
First of all, the seahorse may have become egg bound so that she is swollen with a clutch of ripe eggs that she has been unable to release. Although rare, egg binding is an affliction that sometimes plagues female seahorses and this is what I normally advise hobbyists in that regard:
The only time we normally see a female seahorse with a distended abdomen is immediately after she has hydrated or ripened a clutch of eggs prior to mating, as discussed below.
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.
The mature ova are normally hydrated in the latter stages of courtship, shortly before the copulatory rise and transfer of the eggs that culminates the mating process in seahorses. So it would be unusual for a female to retain hydrated eggs for more than a day or so — ordinarily, if a receptive male is not available to receive the eggs, the female will simply eject them and unceremoniously dump her clutch of eggs on the bottom of the tank.
More information regarding egg binding and a possible treatment for the condition are discussed in the following excerpt from my new book (Complete Guide to the Greater Seahorses in the Aquarium, unpublished):
Egg Binding: a Health Risk for Breeding Females.
Egg binding occurs when a female has ripened (hydrated) a clutch of eggs and is unable to deposit them with a mate or release them for some reason. As more eggs develop, the egg bound female becomes increasing bloated and great pressure begins to build up internally. The abdomen will be very swollen, especially around the vent, and often prolapsed tissue or other material will begin to protrude from the vent as the pressure builds. The affected female will show rapid respiration and may go off her feed. If the pressure cannot be relieved, death results.
Tracy Warland describes a typical case in a female Potbelly (Hippocampus abdominalis) as follows: "Went into the shed one morning to find an adult mare, probably fully mature, in distress. She had been living quite happily in the main tank with about 10 males to meet any desire she might have. Anyway she was lying on the bottom of the tank, panting. I removed her immediately and placed her in sick tank, thought it could be parasites so gave her several 5-minute freshwater baths, but these did not seem to help. I had checked all parameters of large tank the day before so I knew the water was pristine, no other horse was stressed.
When I was putting her back after a freshwater bath, I was supporting her upright for a few minutes to see if she could hitch somewhere. I applied very slight pressure to her belly, and out shot masses of orange stuff. I collected some and checked under the microscope and it looked very much like roe, but the yolk was almost smashed, with globules of a fat-like substance within the centre. We’ve had roe before, due to unsuccessful egg transfer, so we picked up some of bottom of tank and checked it out! I put it down to women’s problems, egg bound, could not discharge unfertilized eggs, these became rotten within her and therefore caused perhaps fever like symptoms."
Egg binding is uncommon in seahorses. Most females have no problem simply dumping their eggs and spilling them on the bottom when a receptive male is unavailable. But there are two circumstances that sometimes promote egg binding. One of them is when breeding seahorses are kept in a tank that’s too shallow. Courtship will proceed normally and the female will hydrate her clutch of eggs in due course, but the pair will then be unable to complete the copulatory rise due to the lack of depth. In such a situation, the female is very reluctant too dump her eggs while a receptive male is standing by, eager to receive them. If she retains the ripened eggs too long in hope that they will be able to complete the egg transfer despite the inadequate vertical swimming space, she may become egg bound.
The other situation that may predispose females to egg binding is when the sexes are segregated. For example, Heather Hall reports that the London Zoo was so successful in breeding and raising the prolific Cape Seahorse (Hippocampus capensis) that, at one point, they were forced to separate the males and females in order to bring a halt to the population explosion that resulted (Bull and Mitchell, 2002, p 30). However, they were soon forced to abandon their experiment in enforced abstinence because it proved stressful to the seahorses and a few of the isolated females began developing swollen abdomens and experiencing difficulty with egg binding when deprived of the opportunity to breed (Bull and Mitchell, 2002, p 30).
There is no ready cure for egg binding and attempts to manually massage the eggs from the body usually only result in internal injuries. However, there is a folk remedy that’s commonly used to treat egg binding in freshwater fish. This treatment consists of placing the affected fish in a bath of Epsom salts (magnesium sulfate) for 10-15 minutes at a dosage of one tablespoon of Epsom salt for every one-gallon of water (Duedall, 2004). The Epsom baths are repeated once a day until the patient recovers (Duedall, 2004).
I have no idea if this remedy would have any affect on a marine fish, but many freshwater hobbyists swear by it, and egg binding is fatal if unresolved so you really have nothing to lose by trying it. Epsom salts are certainly inexpensive and readily available. If you want to give it a go, I suggest administering a 10-15 minute freshwater bath with one tablespoon of magnesium sulfate per gallon added to the bath water. Mix in the magnesium salts thoroughly, aerate the container, and observe the usual precautions for any freshwater dip. Repeat once daily as needed.
As always, prevention is the best cure. If you provide your seahorses with a reasonably tall aquarium and avoid separating the males from the females, there is a very good chance you will never see a case of egg binding.
In short, if your female’s abdomen appears swollen, particularly around the area of the vent, then I suspect that she may be egg bound. The prognosis is poor in such cases, but the condition is not at all contagious and no pathogens of any sort are usually involved, so the rest of your herd should remain unaffected.
Prolapses will often repair themselves once the internal pressure has been relieved, so if you can induce your female to release her clutch of eggs, possibly using the Epsom salts as described above, there is a chance that she may recover. The chances of a good outcome are slim once the pressure from egg binding has reached a point where tissue and compressed ova begin to extrude through the vent. To give you an idea of how much pressure can build up in these cases, a female will often lose 30% of her weight when she drops a clutch of eggs or transfers her ripened eggs to a receptive male. If your female is egg bound, the condition has not yet progressed to the point where a prolapse has resulted, Barbara, so there is a chance she may yet be able to drop her clutch of eggs…
One other possibility is that your female seahorse may have become constipated, particularly if she is eating the frozen Mysis but is no longer producing fecal pellets as she normally would follow me in a good feeding.
Constipation is more common in fishes with laterally compressed bodies such as seahorses and can be caused by overfeeding, a change in diet, certain medications, stress, and rarely an intestinal blockage. The most obvious indication of constipation is an obviously swollen abdomen, particularly in the area of the vent, accompanied by a lack of fecal pellets.
The following cures for constipated fish are often suggested, but I
have no idea if they would be effective for seahorses:
(1) Fast the fish for two days.
(2) After fasting, feed the affected fish with live foods such as brine
shrimp rather than frozen foods.
(3) Soak the fish’s food in cod liver oil or place two drops of cod
liver oil directly in the fishes mouth so that it is swallowed.
(4) induce the fish to eat a single grain of Epsom salt.
Here’s what I would recommend if, you can suspect that your female may be constipated:
Stop feeding the seahorse immediately. Fast her for two days and
observe her closely to see if the constipation is relieved and she
produces any fecal pellets.
While she is fasting, obtain some live adult brine shrimp and cod liver
oil. If she is still not producing normal fecal pellets after two days of
fasting, soak the live adult brine shrimp in water that you’ve added
cod liver oil to for 15-30 minutes, and then feed the brine shrimp that have
soaked in (and hopefully ingested) the cod liver oil immediately to
your seahorse, being careful not to overfeed. Feed her a strict diet
of cod-liver-oil-soaked brine shrimp sparingly for a couple of days and
see if that relieves her constipation.
If that doesn’t relieve the abdominal swelling and induce her to start
eliminating fecal pellets again, you could try tube feeding her with
two drops of the cod liver oil, injecting it directly into her
esophagus so it’s sure to reach her gastrointestinal tract.
Another possibility is that your female may have developed internal gas bubble disease. In that case, its abdomen will be filled with excess gas and the seahorse will be reluctant to move from its perch and attempt to swim because of the strong tendency to float due to positive buoyancy. Internal gas bubble disease is a very serious affliction that is difficult to resolve, but it can be treated by compressing the seahorse at depth and/or using the medication acetazolamide (brand name Diamox).
The remaining possibility is that the abdomen of your seahorse is full of fluid due to kidney failure and/or ascites, Barbara. In that case, the seahorse will be reluctant to release its grip and attempt to swim because of a strong tendency to sink to the bottom due to negative buoyancy. Abdominal dropsy or ascites sometimes responds to the antibiotics doxycycline and kanamycin used together at the same time. In addition, you could consider trying a regimen of Diamox in your hospital tank, if you happen to have the medication on hand. Diamox (the tablet form of acetazolamide) has some mild diuretic properties which could possibly help reduce the swelling in her abdomen and relieve some of the resulting pressure. Diamox is a prescription drug that is the goal to obtain, but it can be used in conjunction with antibiotics, so it’s something to consider if you have the acetazolamide available.
One simple way to determine if your female is struggling with positive buoyancy (i.e., internal gas bubble disease) or negative buoyancy (i.e., ascites or fluid buildup in the abdominal cavity) is to observe her while she is swimming, Barbara. If the seahorse tends to float and must struggle to swim downward, she is having a problem with positive buoyancy; likewise, if the seahorse tends to sink and has difficulty swimming upwards from the bottom, she is having a problem with negative buoyancy. So I would like you to gently induce your seahorse to release its grip on its hitching post, and then release her in midwater in your aquarium and observe her closely to see if she can swim normally, in the typical upright swimming posture of Hippocampus, or if she struggles as described above and tends to either float back up to the top of the aquarium again or tends to sink back to the bottom of the aquarium in. That will provide you with a good indication of whether she has developed internal GBS or conversely a problem with abdominal dropsy are ascites, and you could treat her according.
If not, if your female is not experiencing problems with buoyancy and can swim normally, without floating or sinking, that would be a pretty good indication that either egg binding or constipation is the problem.
Here is the proper way to encourage your seahorse to release its grip and to handle it when performing this simple buoyancy test, Barbara:
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 resolving this problem with your female seahorse and restoring order to good health again, Barbara.