Wow, it sounds like you your aquarium has had its share of ups and downs this past month, but you seem to be doing a fine job of dealing with a series of minor crises and nursing your seahorses through them all.
The bubble on the back of your seahorse’s head is a different form of gas bubble disease (GBD) known as subcutaneous emphysema or external GBD. In this form of GBD, bubbles of gas begin to build up just beneath the skin of the seahorse. These gas-filled pockets are known as subcutaneous emphysema and are the cause of the buoyancy problems in this form of GBD. The characteristic subcutaneous emphysema form most commonly on the tail of the seahorse, and are often known as tail bubbles for that reason, but they can occur anywhere on the seahorse and it’s not unusual to see them on the head or snout of a pony.
Fortunately, this form of GBD responds wonderfully well to treatment with carbonic anhydrase inhibitors, such as acetazolamide (brand name Diamox). The easiest way for you to handle this problem would be to administer Diamox to the male H. erectus orally via feeder shrimp that have been injected with a solution of the Diamox, which will allow you to treat him in the main tank, as I will explain later in this post.
Unfortunately, Mardean, 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 that’s been posted regarding subcutaneous emphysema or external GBD and gas bubble syndrome (GBS) on this forum, and how it’s treated using Diamox, and present that to your family veterinarian and/or your family practitioner. Bring photographs of the seahorse with the bubble on its head 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 affected stallion 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, Mardean, the following source is the one most seahorse keepers have found works best:
Click here: Inhouse Drugstore Diamox – online information
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. That’s why it’s best to plan ahead and line up the medication now, before it’s actually needed.
When you obtained the acetazolamide, Mardean, it can 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, providing your H. erectus stallion is still eating, 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 Diamox baths.
You mentioned that the male with the bubble on the back of his head had developed a bad habit of perching high up in the tank near the overflow right at the surface, and if you have corrected that problem, you may have tipped the balance in his favorite again since the increased hydrostatic pressure at the bottom of your tall 65-gallon aquarium is much greater than it is near the top of the tank, of course, and the increased pressure may cause some of the gas to go back into solution and be resorbed. This condition can also be treated successfully by pressurizing the affected seahorse in a homemade decompression chamber at a depth of about 40 inches, and that is something that you may want to consider if you happen to order the Diamox through the mail and must wait a week or two for it to arrive. Let me know if you would like more information about the recompression/compression cure for GBD, and I can provide you with some instructions for preparing a homemade decompression chamber.
Best of luck getting your seahorse tank back to normal again, Mardean! If you have taken care of the bubble problem from the low water levels, and gradually corrected the pH and water quality parameters, you may be free of problems with GBD in the future.