air bubbles in the end of tail

Dear Paul:

Your male seahorse has developed subcutaneous emphysema of the tail, a form of Gas Bubble Disease (GBD) that is commonly known as external GBD or simply "tail bubbles" by hobbyists for obvious reasons. In cases of subcutaneous emphysema the blisterlike gas bubbles tend to form in the soft tissue of the subcutis at the most distal portion of the tail end can be easily observed with the naked eye. When these are examined microscopically, they are often associated with gas-filled ‘pseudocysts’ lined with endothelial tissue that are suggestive of gas-dilatation of lymphatic vessels. Chronic cases often exhibit fibrosis or a thickening and toughening of the skin around the bubble, and these are the most stubborn cases that are the hardest to cure. But when the condition is detected early, it usually responds very well to treatment with Diamox, as we will discuss later in this e-mail.

Gas Bubble Disease (GBD) 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 GBD. 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 GBD).

Different parts of the body can thus be affected depending on how the
initial gas emboli or micronuclei form, grow and spread. During an
episode of GBD, bubbles may initially form in the blood
(intravascular) or outside the blood (extravascular). Either way,
once formed, a number of different critical insults are possible.
Intravascular bubbles may stop in closed circulatory vessels and
induce ischemia, blood sludging, edema, chemistry degradations, or
mechanical nerve deformation. Circulating gas emboli may occlude the
arterial flow or leave the circulation to lodge in tissue cites as
extravasular bubbles. Extravascular bubbles may remain locally in
tissue sites, assimilating gas by diffusion from adjacent
supersaturated tissue and growing until a nerve ending is deformed or
circulation in nearby capillaries and vessels is restricted. Or,
extravascular bubbles might enter the arterial or venous flows, at
which point they become intravascular bubbles. Extravascular bubbles
can thus become intravascular bubbles, and vice versa, via diffusion
and perfusion. This is important because it means that under certain
conditions extravascular seed bubbles or micronuclei can enter the
bloodstream and migrate from their birth site to other critical areas
as intravascular bubbles. If untreated, the gas bubbles worsen and
the condition is fatal.

The prehensile tail of the seahorse is often affected when conditions are favorable for the formation of such gas emboli because it has a rich blood supply via the dorsal aorta and caudal vein and because the tail is the site where seahorses tend to store their limited fat reserves (the extravascular seed nuclei or emboli that trigger GBD form most readily in adipose tissue due to the higher solubility of certain gases in lipids than in aqueous tissues). Intravascular bubbles are seen in both the arterial and venous circulation, but with vastly greater numbers detected in venous flows (venous gas emboli). The far more numerous venous bubbles are believed to first form in lipid tissues draining the veins. Lipid tissue sites possess very few nerve endings, possibly masking critical insults at first, and veins, which are thinner than arteries, appear more susceptible to extravascular gas penetration.

In seahorses, oxygenated blood is delivered to the tail via the dorsal aorta, a major artery running the length of the body below the spine, and CO2-laden water is returned via the caudal vein which runs along the inside of the tail. In seahorses, venous bubbles often form at the most distal portion of the tail where the oxygen tension is lowest.

Fortunately, Paul, subcutaneous emphysema, the form of GBS your male seahorse has developed, responds extremely well to treatment with carbonic anhydrase inhibitors. The suggested treatment regimen is as follows:

Acetazolamide Baths

The recommended dosage is 250 mg of Diamox (the tablet form of acetazolamide) per 10 gallons with a 100% water change daily, after which the treatment tank is retreated with acetazolamide at the dosage indicated above (250 mg/10 gal) (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.

If you prefer, you can also administer the acetazolamide orally, 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.

Unfortunately, Paul, obtaining Diamox (the tablet form of acetazolamide) can often be a Catch-22 situation for hobbyists. It is 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 that’s been posted regarding GBS and how it’s treated using Diamox and present that to your family veterinarian and/or your family practitioner. Bring photographs of your red seahorse showing the bubbles on its tail 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 the red seahorse 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.

If you ultimately need to go that route, Paul, 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.

In your case, Paul, since the gas filled tail bubbles are so extensive that they are causing the seahorse to float upside down, you may also want to consider lancing the bubbles to relieve the positive buoyancy and speed the healing process. There are two schools of thought regarding lancing the tail bubbles, sir. Some of the pros highly recommend it while others maintain that it should never be done For example, in the case of external GBS or subcutaneous emphysema, Tracy Warland recommends that the external blisterlike bubbles be lanced prior to the first of the Diamox baths (Warland, 2002). Other experts feel that tail bubbles should never be lanced and deflated because it can increase the risk of secondary infections developing. I ordinarily recommend lancing the tail bubbles only when they are so large or numerous that they cause buoyancy problems (the tendency to float) for the seahorse and prevent it from eating properly. Struggling against positive buoyancy can aggravate GBD by acidifying the seahorse’s blood, and of course, keeping the seahorse eating properly is very important to help it make a full recovery. Since that is the case with your male, Paul, I feel lancing the tail bubbles is appropriate in your case.

The "Syngnathid Husbandry Manual for Public Aquariums" recommends aspirating the bubbles after anesthetizing the seahorse and then treating with acetazolamide (brand name Diamox): " Under MS-222, discrete gas bubbles or ‘pseudocysts’ are first aspirated with a 27 ga. needle. The carbonic anhydrase inhibitor, acetazolamide, is then administered…"

If you feel that lancing the tail bubbles to accelerate the healing process is warranted in your case and you don’t feel comfortable anesthetizing the seahorse first, then perform the treatments in a hospital tank and administer an antibiotic to safeguard against secondary infections, and proceed as follows:

Use a fine sterile needle for this and approach each bubble from the side at a very shallow angle, taking extreme care to pierce only the surface of the bubble, not the underlying muscle and tissue of the tail (Warland, 2002). Once the bubble surface has been pierced, apply gentle pressure to the bubble to deflate it and release any air or fluid inside.

Remember, Paul, it is now known that you can combine anitibiotic therapy with Diamox treatments with no risk of dangerous drug interactions. It is therefore advisable to administer a good broad-spectrum antibiotic while you are treating the seahorse in your quarantine tank in order to prevent secondary infections, especially if you lance the tail bubbles. I would recommend an aminoglycoside antibiotic such as kanamycin (e.g., kanamycin sulfate, Kanacin, Kanacyn, Kanaplex, etc.) or neomycin sulfate. But triple sulfa is a reasonable alternative if that’s all that you have on hand or can readily obtain. Redose the quarantine tank with the anitibiotic after you make the water change each day.

Best of luck obtaining the medication you need, Paul! Here’s hoping your male seahorse is feeling much better again real soon.

Respectfully,
Pete Giwojna

Dear Paul:

Okay, that sounds good — it’s excellent that your circle of friends includes a number of doctors that may be willing to help you obtain the acetazolamide (brand name Diamox) and a fine syringe and needle to treat your stallion’s tail bubbles. That would be extremely helpful since the sooner you begin treatment the better the outcome is likely to be.

I would also like to discuss the causes of gas bubble disease (or gas bubble syndrome as I prefer to call it, since it’s not actually a disease process or infection of any sort) and how it can best be prevented in the home aquarium, Paul.

As we were discussing in my previous post, 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).

Different parts of the body can thus be affected depending on how the
initial gas emboli or micronuclei form, grow and spread. During an
episode of GBS, bubbles may initially form in the blood
(intravascular) or outside the blood (extravascular). Either way,
once formed, a number of different critical insults are possible.
Intravascular bubbles may stop in closed circulatory vessels and
induce ischemia, blood sludging, edema, chemistry degradations, or
mechanical nerve deformation. Circulating gas emboli may occlude the
arterial flow or leave the circulation to lodge in tissue sites as
extravasular bubbles. Extravascular bubbles may remain locally in
tissue sites, assimilating gas by diffusion from adjacent
supersaturated tissue and growing until a nerve ending is deformed or
circulation in nearby capillaries and vessels is restricted. Or,
extravascular bubbles might enter the arterial or venous flows, at
which point they become intravascular bubbles. Extravascular bubbles
can thus become intravascular bubbles, and vice versa, via diffusion
and perfusion. This is important because it means that under certain
conditions extravascular seed bubbles or micronuclei can enter the
bloodstream and migrate from their birth site to other critical areas
as intravascular bubbles. If untreated, the gas bubbles worsen and
the condition is fatal.

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.

Reducing the specific gravity and lowering the water temperature in your seahorse tank 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.)

In case you haven’t seen it before, Paul, 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 to see is a 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, if possible, 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 your 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 (Seahorse Sanctuary, Australia) 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 shield or 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, Paul. 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, Paul! Here’s hoping your troubles with gas bubble syndrome are soon a thing of the past.

Respectfully,
Pete Giwojna, Ocean Rider Tech Support

Dear Paul:

Thanks for the update! It’s great to hear that you were able to obtain the Diamox and treat your seahorse, and that your stallion has responded to the medication well.

He is well on the way to recovery now that his tail bubbles or subcutaneous emphysema have cleared up, and it’s always a good sign when the affected seahorse can swim normally again and is eating well. I would continue treating him for a couple of more days until he has had seven days worth of treatments. If everything continues to look good the day after the seventh treatment, you can go ahead and return him to the main tank with the rest of your herd at that time.

Be sure to doublecheck your seahorse tank and correct anything that might be making your ponies susceptible to Gas Bubble Disease, as we discussed in my previous post, in order to prevent this type of problem from occurring again.

It sounds like you are doing a fine job with the treatments, Paul, and hopefully you will never have to deal with another case of GBD.

Respectfully,
Pete Giwojna

Dear Paul:

Yes, sir, a protein skimmer that’s throwing off clouds of microbubbles certainly can contribute to gas bubble syndrome indirectly, so adjusting your skimmer to prevent the release of the microbubbles was an excellent precaution. Well done!

A few microbubbles in the aquarium are ordinarily not a cause for concern, but if your protein skimmer is releasing a ton of them, then you need to address that problem probably. Such microbubbles are not directly harmful to seahorses and are generally only problematic when they contribute to gas supersaturation. If the aquarium water become supersaturated, gas emboli can form in the blood and tissues of the seahorses, resulting in various forms of gas bubble syndrome (GBS).

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).

Microbubbles in the aquarium can sometimes contribute to gas supersaturation in a similar fashion if they are sucked into the water pump and then pressurized as they pass through the filtration system. So you did very well to eliminate the excess microbubbles that your protein skimmer is producing to reduce the chance of that happening. It sounds like it’s releasing a great deal of the microbubbles, which would increase the chances that some of them can be sucked into the aquarium filters and pressurized, which could contribute to gas supersaturation of the aquarium water.

if it’s a relatively new protein skimmer, most likely the skimmer simply needs to be tweaked or adjusted properly in order to eliminate the excess microbubbles it is producing. For example, the water level inside the main chamber of the protein skimmer is a crucial factor for most units. If the water level is too low, it will inhibit foam production. On the other hand, if the water level is too high, it may result in excessive amounts of very wet foam and overflow the collection cup.

Don’t hesitate to contact the manufacturer for troubleshooting tips to help you eliminate the excess microbubbles that are being released. Some protein skimmers have bubble traps available to eliminate excess bubbles from the outflow of the skimmer. Ask the manufacturer if there is one for your particular skimmer.

Best wishes with all your fishes, Paul!

Happy Trails!
Pete Giwojna