Re:Air in Pouch

#4978
Pete Giwojna
Guest

Dear Sandra:

I’m sorry to hear about the problems that you have been having with one of your males. When the problems with pouch gas and positive buoyancy keep recurring, the problem is that more gas keeps continually building up within the pouch again after it is expelled. This is a condition known as chronic recurring pouch emphysema (PE), which is a form of gas bubble syndrome (GBS) and requires stronger methods that simply burping the pouch in order to cure the affliction once and for all.

In other words, right now you are merely treating the symptoms of the problem (the gas that builds up within your male’s pouch) rather than addressing the underlying cause of the problem, which is gas bubble syndrome. In order to resolve recurring pouch emphysema once and for all, it is usually necessary to thoroughly rinse out the male’s pouch and/or treat the seahorse with a carbonic anhydrase inhibitor such as Diamox. This is important because repeatedly burping the male’s pouch or manually evacuating the air can be harsh on the delicate membranes of the pouch over time and may eventually result in tissue breakdown and infections.

In cases like this, Sandra, you will need to try flushing out your stallion’s pouch thoroughly in conjunction with administering the medication Diamox, as described below:

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

In my experience, acetazolmide (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 multiple times, 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 and is also available online from the National Fish Pharmacy. As an alternative, kanamycin also makes it effective pouch wash used by itself.

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. In short, Judy, repeatedly burping the seahorses pouch eventually becomes counterproductive in cases of recurring pouch emphysema, and it is therefore time for you to treat Casper by performing a thorough pouch flush instead.

Here are detailed instructions from Leslie Leddo, myself, and other experienced seahorse keepers explaining different ways to perform a pouch flush:

"Pouch Flush Techniques and Tips"
By Leslie Leddo

You will need:

·A small syringe. I like to use a 1-cc syringe.

·A catheter of some sort. It needs to be something that is plastic, very narrow, cannulated, blunt tipped, semi pliable, but not so soft that it bends from just a bit of pressure, on one end and fits snugly on to the tip of a syringe at the opposite end. Some suggestions would include an a plastic intravenous catheter, with the center introducer needle used to puncture the skin and vein order to introduce the catheter removed, a plastic pipette, or the syringe tips that come inside some of the aquarium test kits. If you have access to an IV catheter any size, between an 18 and 25g will work well.

·A bowl. I like to use something with a wide rim so I have space to move freely and have enough room should I need another pair of hands…i.e., an assistant. The syringe and pipette/catheter are both used to flush the pouch as well as to aspirate the previous days flush from the pouch.

How to prepare the Syringe and Catheter:

Draw about 1cc of the medicated flush solution into the syringe by pulling back on the plunger.

Invert the syringe so the tip is pointed up. With the syringe inverted, gently tap it until all the air bubbles come to the surface just below the syringe tip; with the syringe still inverted depress the plunger until all the air is removed from the syringe and a small amount of the solution is emerging from the syringe tip.

Attach the catheter or pipette to the tip of the syringe, depress the plunger of the syringe to fill (prime) the catheter or pipette with the solution.

Okay, now you are ready to flush the pouch. Proceed as follows:

Gently place the horse in the bowl filled with his own tank water. Very gently and slowly introduce the tip of the catheter through the pouch opening, into the pouch. When you enter the pouch you may meet some resistance. If you encounter resistance when inserting the catheter, I have found that it helps to try different angles, rather than pushing forcefully. I have never dissected a seahorse, but from all the evacuations and flushes I have done it feels to me as if the opening to the pouch is more than a simple opening. It feels like a short tunnel, with folds or pockets of tissue along the walls of the tunnel. I have had to flush/evacuate several different horses. They all seem to be built a bit differently.

I have had success entering the pouch opening straight and then angling the catheter down a bit as well as entering at an angle from the start.

Once you have the catheter tip inside the pouch, depress the plunger of the syringe, flushing the pouch until you see some of the solution coming back out of the pouch. Continue to flush the pouch with about .2 to .3 cc.

Once the pouch has been flushed, you want to leave a small amount of flush inside the pouch. Pulling back on the plunger aspirate the some of the fluid until some of the solution has been removed from the pouch, leaving enough so that the pouch remains softly full, but is not at all taught or tight. Place your horse back in his tank

The next day, prior to the new flush, aspirate the previous days flush from the pouch. Using the syringe with the catheter/pipette attached to the tip, insert it as described above. Pull back on the plunger of the syringe withdrawing the flush from the day before.

Now you are ready to administer the newly mixed flush by repeating the steps described above.

Antibiotic Pouch Washes

If you can obtain a suitable small glass eyedropper with a rubber squeeze bulb, the tip of which you can insert into the pouch orifice, you can use the eyedropper to flush the pouch instead. Otherwise, you’ll have to obtain a small pipette or use a small syringe and catheter for the flushes, as previously described in Leslie Leddo’s pouch flushing tips. You will be flushing the male’s pouch once a day for three consecutive days, using a medicated pouch flush solution.

The first thing you’ll need to do is prepare the pouch flush solution. I recommend using a combination of nifurpirinol and neomycin sulfate for the pouch flushes, since that combo works together synergistically to forms a wide spectrum antibiotic with potent antifungal as well as antibacterial properties (Basleer, 2000). Nifurpirinol and neomycin sulfate are the active ingredients in two different commercial products designed for aquarium use, and both of them should both be readily available at your local fish store. Prepare a 50:50 solution by taking approximately 1/10 teaspoon of nifurpirinol and 1/10 teaspoon of neomycin powder (from a capsule) and mixing them together with about 40 cc (or 2-1/2 tablespoons) of tank water from your seahorse setup. (Nifurpirinol comes in tablet form, so you’ll have to crush a tablet into as fine a powder as possible, using a blender if necessary, and then use 1/10 teaspoon of this nifurpirinol powder for the mixture.) Mix the nifurpirinol powder and neomycin sulfate powder with the tank water very well until the medication is thoroughly dissolved. Avoid any undissolved residue that remains. (You will have to make up a new batch of this solution each day for 3 days.)

If you can’t find both nifurpirinol and neomycin, then you can use either one alone, or substitute kanamycin capsules alone, to make your medicated pouch solution. In that case, just use 1/10 teaspoon of the antibiotic powder and mix it thoroughly with about 20 cc (or 1-1/2 tablespoons) of tank water. Again, make a new batch of pouch-flush solution each day.

And here are instructions from Keith Gentry explaining how to do a pouch-flush directly with Diamox:

Pouch Flush

In cases of recurring pouch emphysema, diamox can be administered as a solution injected into the pouch via an narrow gauge irrigating cannula or plastic 26 or 28 gauge IV catheter sleeve attached to a 0.5 or 1ml syringe (larger syringes should not be used).

Using a blender, mix ½ of a 250mg Diamox tablet with a cup of seawater at the same specific gravity as the tank. Fill the syringe with about .5ml of this solution, avoiding the residue at the bottom of the cup. The seahorse should be held as per the procedure for pouch evacuations.

Insert the catheter sleeve slowly and gently a small way into the pouch opening and inject this solution SLOWLY into the seahorse’s pouch, leaving the solution in the pouch. Make sure you are familiar with the location of the pouch opening.

Never use a metal needle for this procedure.

The procedure may have to be repeated twice to be effective. In stubborn cases, it is recommended to concurrently administer broad spectrum antibiotics. Diamox and antibiotics have been used simultaneously and successfully without appararent side effects.

I believe the dosage of antibiotic is one 250mg tablet of neosulfex per 10 gallons. It’s important you treat the horse in a quarantine tank. Diamox and neosulfex can kill your
biofilter.

For neomycin and sulfa you can use up to 4 times the marine dosage listed on the instruction or are up to 8 times the recommended freshwater dosage. [End quote]

Finally, here are Neil Garrick-Maidment’s instructions for performing his extremely successful pouch flushing procedure:

[open quote]
Hi Pete,

Hope you don’t mind me interjecting on the point about gas bubble in the
pouch but it is important to emphasise a few things.

When I devised and developed this treatment quite a number of years ago, I
was shocked to hear some of the ways people were clearing the bubbles within
the pouch, from cocktail sticks to straws, which caused irreparable damage
to the pouch and the Seahorse. It is vital that great care is taken when
doing this process and the purchase of a fine blunt ended pipette from the
chemist is the best way.

When handling the Seahorse make sure you have a
firm grip with the pouch facing outwards under the water, its best to have
the tail curled around the little finger to add stability. Then insert the
pipette almost vertically, through the pouch opening so the pipette goes
down into the pouch (almost parallel with the body) and not in towards the
body which will cause major internal and secondary problems.

Once the pipette is safely in the pouch then a fine nozzled hand spray (it must be
fine to fit into the end of the pipette) must be used to flush down through
the pipette, you will notice bubbles of gas being vented from the pouch as
you flush the pouch, initially with water from the tank, this stops shock to
the animal and at the same time clears the pouch. This same method (do not
remove the pipette in between stages) should then be used to add medication
etc.

When withdrawing the pipette use a slight twisting motion and remove in
exactly the same direction as it has gone in. The Seahorse will seem a
little shell shocked after this but the immediate release from floating etc
will provide instant relief.

I have had 100% success with this process but
you must be in mind of the Seahorse and its discomfort at all times.
Just before starting make sure you have all your equipment and medication in
place, there is nothing worse than getting part way through and realizing
you have forgotten something.

Hope this helps

Best wishes
Neil
Neil Garrick-Maidment [close quote]

If the aperture to the pouch is too tight to insert a small catheter or tiny pipette, then the next easiest way to release the gas is by performing a needle aspiration, a technique that will work equally well for administering an antibiotic solution should a pouch flush proved necessary.

Needle Aspirations.

It is also very practical to aspirate air or fluid from a bloated pouch using a small hypodermic needle and a syringe (and insulin syringe is ideal for this). The pouch can easily be penetrated from the side and is not harmed by the entrance of the needle. It is a painless procedure that causes the seahorse surprisingly little discomfort, if any.

Remember, when you perform a needle aspiration, you are not penetrating the seahorse’s stomach, but rather the brood pouch that is slung beneath its belly at the base of its tail.

You cannot release the gas or fluid that has built up in your male’s pouch simply by perforating the side of his pouch with a small needle. That’s not what the term "needle aspiration" means. Rather, you need a hypodermic needle and syringe in order to perform a needle aspiration. You must first depress the plunger on the hypodermic syringe to empty all of the air out of the barrel of the syringe, and then carefully insert the hypodermic needle into the side of the pouch, just far enough to penetrate into the central cavity of the pouch, and then gradually withdraw the plunger again, which will extract the gas or fluid from that area of the pouch.

You may need to perform this procedure twice, once from the left-hand side of the pouch and once from the right-hand side of the pouch, since male seahorses in breeding condition develop an septum or internal membrane that divides their pouches roughly into left and right hemispheres. So you may need to aspirate air or fluid from the left side of the pouch, and then repeat the procedure with your hypodermic needle on the right side of the pouch in order to remove all of the trapped gas or fluid from your stallion’s marsupium.

In addition to aspirating trapped gas or fluid, the hypodermic can also be used to flush out the pouch thoroughly either with sterile saline or a medicated solution (an antibiotic or Diamox dissolved in saltwater). Here’s how another hobbyist describes this procedure:

<Open quote>
dear pete, it was time to give the antibiotics due to recurrent swelling of his pouch and i had small iv catheters but i was unable to intubate the opening. either too small or voluntary tightening by the horse. only choice left was an injection with a needle. i used a 29g insulin syringe and first removed whatever air i could. then reinjected approx .5cc mix of neomycin sulfate plus bifuran until distended then withdrew approx half of that and left the remainder in his pouch. a couple of lethargic days followed with little food intake. then he started eating live brine shrimp then the usual mysis. it is now 5 or 6 weeks later and all seems well. before that a diamox bath didnt do much but i stopped the diamox due to what seemed like unfavorable side effects. hard to believe the antibiotic injection worked so well. i gave only one injection as it seems to have worked. thanks again for all your help. he was certainly a goner without the intervention and we are most grateful. best regards sg
<close quote>

One of these techniques will hopefully work well for you, depending on what medications and equipment you have on hand or have access to for performing the pouch flushes.

If the pouch-flushes are unsuccessful in resolving this problem and it keeps re-occurring, Sandra, you can try administering Diamox orally if your stallion is still eating, or as a series of baths if he is not. In addition to performing a pouch flush with antibiotics, stubborn cases of recurring pouch emphysema may require treatment with Diamox, as described below:

Treating Gas Bubble Syndrome with Acetazolamide (brand name Diamox)

Treatment with a carbonic anhydrase inhibitor acetazolmide (brand name Diamox) is helpful in treating internal GBS and overinflated swim bladders due to GBS. As you know, the acetazolmide/Diamox can be administered either as a series of intramuscular injections, orally via feeder shrimp bioencapsulated with the medication, or as baths (prolonged immersion) in your hospital tank.

I will discuss all three methods for administering the Diamox below, Sandra, in case you have access to a veterinarian who is willing to work with seahorses and can administer the injections.

Acetazolamide Injections

The suggested treatment regimen for acetazolmide injections is as follows:

Inject acetazolamide at a dosage of 2-3 mg/kg intradermally or
intramuscularly every five to seven days for up to three treatments.

For best results, add ceftazidime (Fortaz) injections to the
treatment regimen at a dosage of 22 mg/kg intramuscularly every 5-7
days, again for up to three treatments. (Ceftazidime is an antibiotic).

If these drugs prove hard to find, the acetazolamide injections alone appear to be nearly as
effective as the combination treatment.

In order to determine the proper dosage for the intramuscular injections, you need to be able to weigh the seahorses accurately, and you must obtain the injectable form of the medications (it is not feasible to prepare a solution of the medication using Diamox tablets).

Due to their bony exoskeleton, injections are particularly challenging with seahorses. Seahorses store their limited fat reserves primarily in their tail, which is the most muscular part of their body. The meaty part at the base of the tail is best suited for IM injections. If you attempt the intramuscular injections, I would suggest targeting the base of the tail just beneath the pouch using a ventral approach with a shallow angle of attack. The needle should be directed between the scutes/plate margins for ease of penetration through the skin. The external area can be rinsed with sterile saline or a drop of a triple antibiotic ophthalmic solution applied prior to needle penetration.

Acetazolamide can also be administered orally by injecting a solution
made from Diamox (the tablet form of acetazolamide) into feeder
shrimp or the tablets can be used to administer acetazolamide as a
7-10 day series of baths, as explained below:

Acetazolamide Baths (prolonged immersion)

The recommended dosage is 250 mg of acetazolamide per 10 gallons with a 100% water change daily, after which the treatment tank is retreated with the sole light at the dosage indicated above (Dr. Martin Belli, pers. com.). Continue these daily treatments and water changes for up to 7-10 days for best results (Dr. Martin Belli, pers. com.).

The acetazolamide baths should be administered in a hospital ward or quarantine tank. Acetazolamide does not appear to adversely affect biofiltration or invertebrates, but it should not be used in the main tank because it could be harmful to inhibit the enzymatic activity of healthy seahorses.

Using the tablet form of acetazolamide (250 mg), crush the required amount to a very fine powder and dissolve it thoroughly in a cup or two of saltwater. There will usually be a slight residue that will not dissolve in saltwater at the normal alkaline pH (8.0-8.4) of seawater (Warland, 2002). That’s perfectly normal. Just add the solution to your hospital tank, minus the residue, of course, at the recommended dosage:

Place the affected seahorse in the treatment tank as soon as first dose of medication has been added. After 24 hours, perform a 100% water change in the hospital tank using premixed water that you’ve carefully aerated and adjusted to be same temperature, pH and salinity. Add a second dose of newly mixed acetazolamide at the same dosage and reintroduce the ailing seahorse to the treatment tank. After a further 24 hours, do another 100% water change and repeat the entire procedure until a total of up to 7-10 treatments have been given. About 24 hours after the final dose of acetazolamide has been added to the newly changed saltwater, the medication will have lost its effectiveness and the patient can be returned directly to the main seahorse tank to speed its recovery along.

One of the side affects of acetazolamide baths is loss of appetite. Try to keep the affected seahorse eating by plying it with its favorite live foods during and after treatment, until it has fully recovered.

The seahorse usually show improvement of the tail bubbles within three days. Dr. Martin Belli reports they nearly 100% success rate when this treatment regimen is followed for 7-10 days, and most cases clear up in less than a week. For best results, the Diamox should be used in conjunction with a good broad-spectrum antibiotic to help prevent secondary infections. A good aminoglycoside antibiotic such as kanamycin or neomycin would work well for this.

If you prefer, you can also administer the acetazolamide orally, Sandra, which is an excellent option as long as the affected male is still eating aggressively, which will allow you to treat the affected seahorse in the main tank amidst familiar surroundings and in the company of its tankmates where it is the most comfortable. You get the acetazolamide into the food by preparing a solution of the medication, as described below, and then injecting it into live feeder shrimp or even the large Piscine Energetics frozen Mysis relicta. The medication is deactivated fairly quickly once you prepare the solution for injecting, so you must prepare a new acetazolamide solution each day during the treatment period. Here’s how to proceed:

Administering Acetazolamide Orally

I have found that acetazolamide is often more effective when it’s ingested and administering the medication orally allows you to treat the seahorse in the main tank where he’s most comfortable and relaxed.

If you can obtain a small syringe with a fine needle, the acetazolamide solution can simply be injected into feeder shrimp or even frozen Mysis. Mic Payne (Seahorse Sanctuary) used this method of administering acetazolamide successfully when he had recurring problems with GBD due to maintaining a population of Hippocampus subelongatus in shallow tanks only 16-inches (40 cm) deep:

"Seahorses maintained in this system are susceptible to gas bubble disease. Specimens with bubbles around the eyes or under the epidermis of the tail are readily treated with acetazolamide (Diamox tablets 250 mg). Mix a very small amount of crushed tablet with water and inject it into several glass shrimp that are then frozen. These are then fed to the target animal at the rate of two per day for four days. Bubbles disappear on the second day."

Hawaiian volcano shrimp or red feeder shrimp (Halocaridina rubra) work great for this. If a fine enough needle is used, they will survive a short while after being injected — long enough for their twitching and leg movements to attract the interest of the seahorse and trigger a feeding response.

Leslie Leddo reports that a 1/2 cc insulin syringe with a 26-gauge needle was ideal for injecting frozen Mysis or live red feeder shrimp. They plump up when injected and ~1/2 cc is about the most of the solution they can hold. There bodies will actually swell slightly as they are slowly injected and excess solution may start to leak out. The 26-gauge needle is fine enough that it does not kill the feeder shrimp outright; they survive long enough for the kicking of their legs and twitching to assure that they will be eaten.

Administering the Diamox orally in this way is the least stressful way to medicate the seahorse, so you may want to consider trying that first before you resort to the IM injections or Diamox baths.

Unfortunately, Sandra, obtaining Diamox (the tablet form of acetazolamide) can often be a Catch-22 situation for hobbyists. It is a carbonic anhydrase inhibitor — a prescription drug often used for treating glaucoma, hydrocephaly, epilepsy, congestive heart failure, and altitude sickness in humans, so you have to get it from your Vet or perhaps your family doctor. Unfortunately, Veterinarians are often unfamiliar with Diamox — it’s very much a people med and unless you find a Vet that works with fish regularly, he or she will probably never have heard of gas bubble disease or treating it with carbonic anhydrase inhibitors. Many pet owners are on very good terms with their Vets, who are accustomed to prescribing medications for animals, so it’s often best to approach your Vet first about obtaining Diamox despite the fact they may never have heard of it until you brought it to their attention. Your family doctor, of course, will be familiar with such medications and have Diamox on hand but it can sometimes be difficult to get your MD to jump that final hurdle and prescribe it for a pet. Either way, it can be tough to get the medication you need under these circumstances.

However, I would exhaust those possibilities first before I considered an online source for the Diamox. Print out some of the detailed information from this post regarding pouch emphysema and gas bubble syndrome (GBS), and how it’s treated using Diamox, and present that to your family veterinarian and/or your family practitioner. Bring photographs of Casper and be prepared to bring the seahorse in for a visit, if necessary. (Veterinarians are prohibited by law from prescribing medications to treat an animal they have not personally seen and examined. If you have had a close personal relationship with your vet over a period of years, they are often willing to bend that rule in the case of fish, but you may well have to bring Casper in for a quick checkup to get the desired results.)

If not — if neither your Vet or family physician will prescribe Diamox — then there are places you can order Diamox online without a prescription, but save that for a last resort. (You can’t always be certain of the quality of the medications you receive from such sources; in some cases, you even need to be concerned about counterfeit drugs, although Diamox certainly shouldn’t fall into that category.) The medications will take a week or two to arrive, which is troublesome when your seahorse is ailing and needs help ASAP. And, as you know, customs officials can confiscate such shipments, although that very rarely happens with this particular medication.

If you ultimately need to go that route, Sandra, the following source is the one most seahorse keepers have found works best:

Click here: Inhouse Drugstore Diamox – online information
http://www.inhousedrugstore.com/neurological/diamox.html

They offer 100 tablets of Diamox (250 mg) for around $20 US, but they ship from Canada by mail, which usually takes a little under two weeks for delivery.

While you are working to line up the Diamox, Sandra, there are a couple of other things that you can do to provide your stallion with some immediate relief in the meantime. For example, after you flush out your male’s pouch, gradually reducing the water temperature and lowering the salinity of the aquarium can minimize problems with pouch emphysema and other forms of gas bubble syndrome (GBS), and will also make the seahorse less buoyant, which will make it easier for him to swim and eat. Reducing the specific gravity to at least 1.020 is helpful, but reducing it all the way to 1.015-1.017 is even better, providing there are no delicate corals or invertebrates in the aquarium that would not tolerate the reduced salinity.

Gradually lowering the salinity or specific gravity is done as if performing a normal water change, except that the replacement water is simply treated tap or RO water without the salt (Don Carner, pers. com.). (If the replacement water is RO/DI or other softened source, then a buffering agent should be employed to prevent pH and alkalinity drops; Thiel, 2003.) Make sure the freshwater you add is thoroughly mixed with the remaining saltwater in the tank as you proceed. This will assure that your salinity/specific gravity readings are accurate. Monitor the lowering closely so as to not reduce it too fast. Achieving the desired specific gravity (1.015-1.017) over a period of several hours is fine (Don Carner, pers. com.). The bacteria colony in the biofilter will survive, the seahorses and fish will survive just fine, and your cleanup crew should also be unaffected (Don Carner, pers. com.).

CAUTION! When lowering the salinity or specific gravity in your seahorse tank, be very careful as you add the freshwater when you approach the target salinity. You do NOT want to overshoot the mark and drop the salinity too far! Seahorses tolerate low salinity very well up to a certain point, but they cannot withstand salinities below 13.3 ppt (specific gravity = 1.010) indefinitely. Salinities below 1.010 may be fatal to seahorses in a matter of days, if not hours. Just take care when the specific gravity in your seahorse tank is nearing the desired level of 1.015-1.017 and you should be in great shape. There is a big enough difference between a specific gravity of 1.015-1.017 and the dangerous level of 1.010 to provide a large margin for error and make this process very safe.

Once you have reduced the specific gravity in your seahorse tank to 1.015-1.017, you can maintain it at that level indefinitely thereafter. When it aquarium has had an outbreak of gas bubble syndrome, reducing the specific gravity to 1.015-1.017 has many benefits. It makes it easier for the seahorses to osmoregulate, increases the amount of dissolved oxygen the water can hold it makes it easier for the seahorses to breathe, helps eliminate protozoan parasites and ectoparasites in general, and helps to minimize problems with gas supersaturation and therefore GBS.

But if you should want to return the specific gravity in your seahorse tank to normal at some point for any reason, be sure to do so very gradually. In that case, when you are ready to return the system to normal salinity, simply reverse the process, remove some of the low salinity water in the aquarium and replace it with high salinity water. Take your time and raise the salinity slowly and gradually. Fish can become dehydrated if the salinity is increased too rapidly, so be methodical and raise the salinity over a period of several days. Don’t hesitate to take a full two weeks to return the specific gravity to normal levels again in small increments. The salinity can be reduced relatively rapidly very safely, but it must be raised again very gradually in order to avoid the risk of dehydration.

Best of luck treating your male’s pouch gas, Sandra. If you don’t already have one, you might want to consider obtaining a pouch kit from Ocean Rider in case these problems persist.

Finally, let’s discuss gas bubble syndrome in more detail and go over some of the other measures the home hobbyist can take to prevent problems with GBS in the future. This will help to explain why your stallion is experiencing pouch gas problems.

Gas bubble syndrome (GBS) is a mysterious, widely misunderstood affliction that can take on many different incarnations. As you know, gas bubble syndrome is believed to be caused by gas emboli forming within the tissue of heavily vascularized portions of the seahorse’s anatomy — the placenta-like brood pouch of males, the eye, the muscular prehensile tail — and it can take several different forms depending on where the bubbles or emboli occur. When it occurs in the brood pouch of the male, chronic pouch emphysema or bloated pouch results, leading to positive buoyancy, which is by far the most common form of GBS. When it occurs in the capillary network behind the eye (choroid rete), Exopthalmus or Popeye results, and the eye(s) can become enormously swollen. When it affects the capillary network of the gas bladder (the rete mirabile), hyperinflation of the swimbladder occurs, resulting in positive buoyancy. When it affects the tail or snout, external gas bubbles (i.e., subcutaneous emphysema) form just beneath the skin and look like raised blisters. When intravascular emboli occur deep within the tissue and occlude blood flow, generalized edema results in the affected area. Or extravascular emboli may cause gas to build up within the coelom, often resulting in positive buoyancy and swelling or bloating of the abdominal cavity (internal GBS).

The mechanisms by which the gas emboli can spread and grow, and the type of insults that can result are therefore fairly well known, but the etiology of GBS is otherwise still poorly understood, and there are many theories as to what causes the gas embolisms to form in the first place. Nitrogen gas supersaturation of the water, the unique physiology of the male’s brood pouch, malfunctions of the pseudobranch or the gas gland of the swim bladder, stress-related changes in blood chemistry that affect the oxygen-carrying capacity of hemoglobin, infection with gas-producing bacteria — all these and more have been advanced as mechanisms that could trigger the formation of the gas embolisms at some point. Very likely GBS has multiple causes, but most experts now believe it is due to physical conditions in the seahorse tank rather than any sort of pathogen, and I would be happy to share my thoughts on the matter with you, for whatever it’s worth.

For starters, let me stress that if it’s very unlikely that any sort of disease organisms or pathogen causes GBS. It is not at all contagious and does not appear to spread from seahorse to seahorse. To my knowledge, no one has ever been able to isolate a pathogen from the marsupium of the male with pouch emphysema or from the subcutaneous emphysema that characterize seahorses with tail bubbles. If bacteria play a role in GBS, I am confident it is only as a secondary infection.

In other words, gas bubble syndrome is not a disease that seahorses contract after being exposed to a pathogen of some sort, but they will often develop the condition when kept in a system that exposes them to gas supersaturation, insufficient water depth, stress, inadequate water circulation, a bacteria-laden substrate or other environmental factors conducive to the formation of gas emboli. In other words, it is an environmental disease, triggered by certain conditions within the aquarium itself. In my experience, the environmental triggers that are most often associated with GBS are as follows:

1) Insufficient depth (aquaria that are less than 20 inches deep are very susceptible to GBS, and the taller the aquarium is, the more resistant it will be to GBS).

2) Gas supersaturation of the aquarium water, which can lead directly to the formation of gas emboli within the blood and tissues of seahorses.

3) Changes in the seahorse’s blood chemistry (i.e., acidosis). Anything that tends to acidify the blood of the seahorses can result in GBS, including stress, low levels of dissolved oxygen and/or high levels of CO2, and low pH in the aquarium water, among other factors.

Maintaining your reduced specific gravity and water temperature are good ways to minimize future problems with GBS due to gas supersaturation, but there are a number of other things to keep in mind in that regard as well.

For example, tall aquariums minimize problems with GBS because the deeper the water and the greater the hydrostatic pressure, the more dissolved gases the water (and the seahorse’s blood) can hold in solution. By the same token, the shallower the aquarium and the less water pressure there is, the less dissolved gases the water can hold and the more likely gas is to come out of solution and form gas emboli (i.e., seed bubbles) in the blood and tissues.

The point is that the greater hydrostatic pressure at increased depth is known to protect seahorses against GBS, whereas the reduced hydrostatic pressure in shallow aquaria is known to be conducive to gas bubble syndrome. I have found that GBS is a very common problem for seahorses in home aquariums that are less than 24-inches tall, whereas there is considerable evidence that tanks 3 feet deep or more provide a measure of protection against GBS. This is because the gas emboli that cause GBS form more readily at reduced hydrostatic pressure, and will go back into solution again if the hydrostatic pressure is increased sufficiently, and obviously the deeper the aquarium the greater the hydrostatic pressure at the bottom of the tank. (In fact, seahorses with GBS can often be cured by submerging them at depths great enough to recompress them (> 10 feet) and cause the gas to go back into solution.)

Here is some information that reviews the most common aquarium stressors, among other causes of GBS, and discusses some simple methods for minimizing problems with GBS. Please look it over closely and see if any of these factors may have contributed to this problem in your case:

Preventing Gas Bubble Syndrome

Since GBS is caused by physical factors in the seahorse setup, when the affliction crops up, it’s a red flag that indicates that there’s something amiss with the conditions in your tank. With that in mind, I would like to quickly review some of the preventative measures aquarists can take to minimize problems with Gas Bubble Syndrome:

(1) Aquarium options (Giwojna, Jan. 2004):

Taller is better. When shopping for a seahorse setup, opt for the tall or high model of the largest aquarium you can reasonable afford and maintain. If the tank is too short, male seahorses may not be able to get enough pumping action in as they ascend and descend during courtship displays and mating (the copulatory rise) to flush out their pouches and cleanse them properly (Cozzi-Schmarr, 2003). This can contribute to bloated pouch, a type of pouch emphysema.

As a rule, your seahorses require a minimum of three times their height (total length) in vertical swimming space in order to mate comfortably and help avoid this sort of pouch gas problem.

Other forms of GBS are also believed to be depth related, but the aquarium must be greater than 30 inches deep to provide any significant protection against them, which is not feasible for most hobbyists (Giwojna, Jan. 2004). As an example, a water depth of at least 3 feet is known to protect the Hawaiian seahorse (Hippocampus fisheri) against GBD (Karen Brittain, pers. com.).

If you’ve had a problem with GBS in the past, look for a tank at least 20-30 inches tall, reduce your water temp to 68°F-72°F, reduce the specific gravity of the aquarium water, and avoid overly tall hitching posts that reach near the water’s surface (Cozzi-Schmarr, 2003). You want to encourage the seahorses to hang out near the bottom in order to take advantage of every inch of depth the aquarium can provide.

(2) Filtration options (Giwojna, Jan. 2004):

Gas supersaturation of the water can occur whenever the dissolved gas pressure in the water is greater than the atmospheric pressure. When that happens, the dissolved gases in the seahorse’s tissues are no longer in equilibrium with the surrounding aquarium water, causing gas to move into the area with lower partial gas pressure — the tissues and blood of the seahorse – and come out of solution, forming gas emboli! Providing proper filtration, circulation, and aeration can help prevent this.

Add:
Trickle filter (acts as a de-embolizing tower or degassing column in a limited fashion).
External filter that returns water as a "water fall" or a canister filter with a spray bar return positioned so that it roils the water surface.
Sump with strong aeration.
Overflow drains, as opposed to siphon/suction tubes.
Surface agitation to facilitate efficient gas exchange.
Increased circulation and water movement.
Extra airstone(s) just below the surface of the water.

Having a trickle filter, water "falling" into the tank as it’s returned, or strong aeration and surface agitation in the tank or the sump will help off-gas any supersaturated dissolved gases (Giwojna, Jan. 2004). This will also help off-gas a build up of CO2 and the associated pH drop that some tanks experience when the lights go off and photosynthesis has no longer taking place (Giwojna, Jan. 2004). The off gassing or degassing takes place only at the very air/water interface, so you want to spread the water into very thin sheets and let it be in contact with the atmosphere for an extended period (Robin Weber, pers. com.). That is precisely what a degas column does by trickling water over solid media open to the atmosphere, and if properly maintained and operated, a wet/dry trickle filter or biowheel filter can often perform the same function to a limited extent (Jorge A. Gomezjurado, pers. com.). For best results, the outflow from a trickle filter should go into a baffled chamber that will allow bubbles to dissipate before they enter pumps or plumbing restrictions (J. Charles Delbeek, pers. com.).

Avoid:
Airstones, air lifts, bubble wands, etc., that are submerged deeper than 18 inches.
Leaky pumps.
Subsurface entry of the inflowing or recirculating water.
Protein skimmers that generate a bubble column by injecting air under pressure at depth.

On small, closed-system aquariums, supersaturation is often due to the entraining of air on the intake side of a leaky pump, which then chops the air into fine microbubbles and injects it into the water (Cripe, Kowalski and Phipps, 1999). Water and air are thus mixed under high pressure and forced into the water column, which can result in gas supersaturation. An air leak in inflowing or recirculating water that enters the tank below the surface can cause the same thing (Cripe, Kowalski and Phipps, 1999). Allowing the water to splash before it enters the tank is a simple way to prevent this from happening. The splashing helps the water to expel excess gas and reach equilibrium with the ambient air pressure (Giwojna, Jan. 2004).

Likewise, airstones, air lifts, bubble wands and the like can cause problems if they are too deep because they will cause gas to dissolve in water to match the ambient pressure (the current atmospheric pressure) PLUS the pressure of the water column above the stone. If they are immersed at a depth greater than 18 inches, the pressure of the water column above them may be sufficient to cause low-level gas supersaturation of the water, especially when there is little atmosphere/water interface (Colt & Westers, 1982). For example, Robin Weber found that airstone submerged in reservoirs 3 feet deep produced gas supersaturation at the Monterey Bay Aquarium. The airstones produced supersaturation at a level of about 104%, and the only cases of GBS she has ever observed at the aquarium occurred in the most supersaturated exhibits. So keep your airstones shallow!

Protein skimmers that inject air under pressure at depth, or produce bubbles a foot or more below the surface, can be problematic for seahorses and other fish fry again because that can cause gas to dissolve in the aquarium water at ambient pressure (the current atmospheric pressure) PLUS the pressure of the water column above the bubbles. Under certain circumstances, this can cause low level gas supersaturation of the water and contribute to problems with gas bubble disease (Colt & Westers, 1982) in syngnathids (i.e., seahorses and pipefish). Other skimmers can also cause problems by releasing clouds of microbubbles into the aquarium, which is unsightly and can contribute to certain forms of gas bubble syndrome in seahorses and pipefish such as subcutaneous emphysema, chronic pouch emphysema, Exopthalmia, and hyperinflation of the gas bladder under certain circumstances. (Problems can result if the microbubbles are drawn into the filters or water pumps and pressurized in the process.) So if you have had problems with GBS in a home aquarium filtered by a protein skimmer, consider removing or disabling the protein skimmer to determine if that makes a difference for the better…

(3) Eliminate stress (Giwojna, Jan. 2004):

Avoid overcrowding.
Avoid aggressive tankmates.
Avoid heat stress and temperature spikes.
Install a titanium grounding probe to eliminate stray voltage.
Avoid exposing the seahorse tank to excessive noise or heavy foot traffic.
Use a cork or Styrofoam aquarium pad beneath the tank to deaden vibrations.

Stress has been linked to GBS in seahorses via the following mechanism: chronic or prolonged stress causes changes in the seahorse’s blood chemistry (acidosis), which in turn affects the oxygen-carrying capacity of certain types of hemoglobin, and the reduced oxygen-carrying capacity of hemoglobin can then causes embolisms to form in the blood.

The excess of protons (H+) under acid conditions also causes carbonic anhydrase to shift to producing CO2 from carbonic acid in the bloodstream, and the CO2 that results can likewise lead to gas embolisms under certain circumstances (Giwojna, Jan. 2004).

Mic Payne is one of the professionals who feel GBS is most likely a stress-related affliction. He believes it is often a result of chronic stress due to antagonistic behavior by overaggressive males, particularly if they are overcrowded (Payne, pers. com.). Exposing our seahorses to any type of stress may leave them predisposed to GBS (and vulnerable to many other diseases as well). Reduce the stress levels on our seahorses and we reduce the incidence of GBS accordingly (Giwojna, Jan. 2004).

(4) Maintain optimum water quality (Giwojna, Jan. 2004):

Don’t overfeed and remove leftovers promptly.
Employ an efficient cleanup crew.
Practice sound aquarium management and maintenance.
Monitor the aquarium parameters regularly.
Maintain total alkalinity and keep your pH between 8.1-8.4
Maintain a strict schedule for routine water changes.
Gradually reduce the water temperature to increase the amount of dissolved gases it can hold.
Reduce the salinity in the main tank to increase the amount of dissolved gases the water can hold.

When he was experimenting with possible treatments for GBS, Paul Groves (Head Aquarist at Underwater World in Perth, Australia, at the time) was able to produce all the different forms of GBS in a control group of Hippocampus breviceps simply by exposing them to a dirty, bacteria-laden substrate. His seahorse setup was far better than any hobbyist could hope for — an open system with 100% flow through from the ocean and a live sand base, yet all the seahorses in the tank eventually developed GBS (Groves, pers. com.). Males with chronic pouch gas were the first to appear, followed by specimens with internal GBS, and finally subcutaneous gas bubbles appeared on the tails and snouts of the others Groves, pers. com.). The weakness of Paul’s setup was poor circulation, and for experimental purposes, he deliberately allowed fecal matter and uneaten nauplii to build up on the bed of live sand. (Groves found that antibiotics were totally ineffective in treating GBS, but he eventually cured 10 of the 12 affected seahorses by pressurizing them at a depth of 4 meters.)

It is not clear whether stress from the dirty conditions or exposure to such a high density of bacteria triggered the problem in this case, but the lesson is loud and clear all the same — it pays to keep those aquariums clean (Giwojna, Jan. 2004)! If we keep our seahorses setups clean, we will keep our problems with GBS to a minimum (Giwojna, Jan. 2004).

Maintaining the proper pH is especially important for seahorses, since low pH in the aquarium can contribute to the acidosis under certain circumstances, leading to gas embolisms via the same mechanisms as stress-induced GBS (Giwojna, Jan. 2004).

Likewise, it’s important to remember that the warmer the water, the less dissolved oxygen it can hold. Elevated water temperatures increase the metabolism of your seahorses, and therefore their consumption of oxygen, at the same time that the rise in temperature is reducing the amount of dissolved oxygen in the water. That creates a dangerous situation for seahorses and may well result in respiratory distress and rapid, labored breathing, as well as contributing to asphyxia and gas supersaturation under certain circumstances. Reducing the water temperature will increase the amount of dissolved oxygen and other gases the water can hold before it becomes saturated, reducing the chances of gas supersaturation (hence GBS) and hypoxia accordingly.

There is also an inverse relationship between salinity and dissolved oxygen. The higher the specific gravity or salinity, the less dissolved oxygen (and other dissolved gases) the water can hold. By the same token, the lower the salinity or specific gravity, the more dissolved gases the water can hold. Sometimes the specific gravity in a seahorse tank can creep up unbeknownst to the aquarist due to evaporation of the aquarium water, and the higher the specific gravity gets, the lower the dissolved gas levels in the aquarium will be and the greater the chances that the aquarium water could become supersaturated with dissolved gas. Lowering the specific gravity in the home aquarium as to at least 1.020 is a good way to eliminate such potential complications. Seahorses will be perfectly comfortable at a specific gravity of 1.015-1.017 and can tolerate a specific gravity as low as 1.010. Reducing the salinity will help prevent potential problems with gas supersaturation and therefore GBS.

(5) Water changing precautions (Giwojna, Jan. 2004):

It’s an excellent idea to use Reverse Osmosis (RO) or Deionized (DI) or RO/DI water for your changes because it’s much more pure than tap water. However, water purified by such methods is very soft and must be buffered before it’s used so it won’t drop the pH in your aquarium when it’s added (Giwojna, Jan. 2004).

When mixing saltwater for your marine aquarium, it’s important to fill your container with all the water you will need BEFORE adding the salt mix. In other words, if you are mixing up 5 gallons of new saltwater, fill the mixing container with 5 gallons of water and then add the salt. If you do it the other way around — dump the salt mix in the container and then start filling it with water, the water can become saturated with salt to the point that the calcium precipitates out. This calcium precipitation will turn the water milky and can also lower the pH to dangerous levels (Giwojna, Jan. 2004).

Water changes can also be a problem because of the supersaturation of gases in tap water. Tap water distribution systems are maintained under pressure at all times, both to insure adequate flow and to prevent polluted water from outside the pipes from entering in at leaks. Any additional gas introduced into these pipes (from a leaky manifold, for example) will be dissolved at these are higher partial pressures, and will often be supersaturated when it emerges from the tap (Giwojna, Jan. 2004). Also, as we have previously discussed, gases are more soluble in cold water than warm, so when gas-saturated cold water emerges from the tap and warms up in an aquarium, or is warmed up and preadjusted to aquarium temps prior to making a water change, the water can become supersaturated (Giwojna, Jan. 2004). This must be avoided at all costs because gas supersaturation is one of the factors that can contribute to Gas Bubble Syndrome in seahorses and other fish.

To prevent this, tap water should be allowed to sit for several days beforehand or gentle aeration can be used to remove gas supersaturation before a water change (just make sure your airstones are not be submerged greater than 18 inches while you’re aerating your freshly mixed water; (Giwojna, Jan. 2004)). Some brands of artificial sea salt also produce low levels of ammonia immediately after mixing with water, and aging or aerating the newly mixed water as described above will dissipate this residual ammonia.

Most of the above is mentioned for future reference for hobbyists that have well-established seahorse tanks — I realize there aren’t many modifications you can make after the fact, once your system is already up and running (Giwojna, Jan. 2004). But there are a few things you can try with your existing system that should help.

First of all, whenever you find yourself dealing with an environmental disease such as GBS, a water change is an excellent place to start. At the first sign of GBS, I suggest you combine a 25%-50% water change with a thorough aquarium clean up (Giwojna, Jan. 2004).

Secondly, consider adding an ordinary airstone to your tank, anchored just beneath the surface of the water. That will add surface agitation, extra aeration, and better gas exchange at the air/water interface (Giwojna, Jan. 2004). Unless you’re quite certain your system already has plenty of water movement, it is also advisable to add a small powerhead for extra circulation (Giwojna, Jan. 2004). Seahorses can handle more water movement than most folks realize, and you can always turn it off during feedings. Just screen off the intake for the powerhead as a precaution so it can’t accidentally suck up a curious seahorse (Giwojna, Jan. 2004).

Thirdly, I recommend that home hobbyists who have had a problem with GBS in the past reduce the salinity in their seahorse tanks to at least 1.020 in order to increase the amount of dissolved gases the water can hold before it become saturated. Reducing the specific gravity to 1.015-1.017 is even better in most cases, providing you aren’t keeping live corals or delicate invertebrates in your seahorse tank. Likewise, reduce the water temperature in tanks with a history of GBS to around 68°F-72°F in order to increase the amount of dissolved gases the water can hold before it become saturated. Both these simple measures will help prevent gas supersaturation and reduce future problems with GBS accordingly.

Finally, use shorter hitching posts and holdfasts that will confine your seahorses to the bottom half of the aquarium and reduce the water temperature. Shorter hitching posts will get the maximum benefit from whatever depth your tank can provide, and lowering the water temperature and specific gravity allows the water to hold more dissolved gases, which can help avoid any tendency toward supersaturation (Cozzi-Schmarr, 2003).

Those simple measures may make a big difference. Just maintain good water quality, provide your seahorses with the stress-free environment, add a shallow airstone and perhaps an extra power head to provide better water movement and gas exchange, remove your protein skimmer as a precaution, keep things cool and reduce the water temperature in your seahorse tank, and you can reduce your risk of GBS considerably.

That’s my thinking with regard to preventing GBS, Sandra. I suspect that very few of the factors mentioned above apply to your seahorse setup, but they are common problems for many home aquarists.

Best of luck with your seahorses and all of your projects, Judi! Here’s hoping your troubles with chronic recurring pouch emphysema and gas bubble syndrome are soon a thing of the past.

Respectfully,
Pete Giwojna, Ocean Rider Tech Support


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