Diamox

Dear JM:

Very good, sir! Acetazolamide (brand name Diamox) is very effective in treating external gas bubble syndrome, more commonly known as subcutaneous emphysema or tail bubbles, but it is a prescription drug that can be very difficult for home hobbyist to obtain. Obtaining the necessary medication is half the battle, and you have already accomplished that, JM. Well done.

The medication can be administered orally, sir, which will allow you to treat the affected seahorse in the main tank without setting up a hospital tank or treatment tank. But you will have to take precautions to make sure that the other seahorses in the aquarium do not eat the medicated Mysis or medicated feeder shrimp. Acetazolamide is a carbonic anhydrase inhibitor and it can be harmful to inhibit the enzymatic activity of healthy seahorses.

Also, bear in mind that the acetazolamide/Diamox has a bitter taste, so that it needs to be injected into the feeder shrimp or frozen Mysis in order to ensure that the seahorses will swallow it. Otherwise, the ailing seahorse will simply spit out the nasty tasting medicated Mysis, and it must be ingested to do any good.

If necessary, you may need to bite the bullet and set up a hospital tank for the seahorse so that you can administer the acetazolamide as a series of baths treatments, JM. I will provide instructions for both methods of administering the medication below, and if you need me to advise you on setting up a simple hospital tank or treatment container for the regimen of Diamox baths, just let me know, and I would be happy to do so right away.

Subcutaneous emphysema (commonly known as tail bubbles or external GBS) can be successfully treated by a prolonged immersion in a series of Diamox baths or by administering the Diamox orally via feeder shrimp that have been injected with a solution of the medication. This method requires 5 or more 250 mg Diamox tablets (depending on the size of the hospital tank or treatment tank).

The Diamox can also be administered orally after injecting a solution of it into live feeder shrimp or even large frozen Mysis, and this technique also requires several of the 250 mg Diamox tablets in order to complete the treatment regimen.

I will discuss each of these methods of treatment in more detail below, JM.

Once you have obtained the acetazolamide (brand name Diamox), it is very effective in treating subcutaneous emphysema or tail bubbles when it is either administered orally by injecting a solution made from Diamox (the tablet form of acetazolamide) into feeder shrimp or when it is administered as a 4-8 day series of baths (and it can also be easily administered as a pouch wash, but that is more appropriate when treating pouch emphysema than tail bubbles), as explained below:

Acetazolamide Baths (prolonged immersion)

The recommended dosage is 250 mg of acetazolamide per 10 gallons (25 mg/gallon) with a 100% water change daily, after which the treatment tank is retreated with the acetazolamide at the dosage indicated above (Dr. Martin Belli, pers. com.). Continue these daily treatments and water changes for a minimum of 4 consecutive days (stubborn cases may need to be continued for twice as long, or up to 8 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 4-8 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 effects 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 affected seahorse typically show improvement of the tail bubbles within three days, in which case the four-day series of Diamox baths will resolve the situation. Dr. Martin Belli reports they nearly 100% success rate treating subcutaneous emphysema when this treatment regimen is followed for 4-8 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 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. However, administering an effective dose of the medication orally can sometimes be difficult to accomplish since the seahorses don’t always accept the medicated Mysis (apparently the Diamox is not particularly tasty).

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 GBS 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. Their 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, depending on the form of GBS you are treating, may want to consider trying injecting feeder shrimp with the solution of the medication first before you resort to the Diamox baths or pouch flushes.

Best of luck resolving your stallion’s problems with external gas bubble syndrome, JM.

Respectfully,
Pete Giwojna, Ocean Rider Tech Support