Dear Martin:

Pete Giwojna

Dear Martin:

No, sir, you do not want to use the acetazolamide (brand name Diamox) to treat the main tank with all of the seahorses. Although the Diamox is an effective medication for treating most common forms of gas bubble syndrome (GBS), it functions as a carbonic anhydrase inhibitor, and it can be harmful to inhibit the enzymatic activity of the healthy seahorses.

You’ll need to administer the medication in a hospital tank or quarantine tank or a treatment container of some sort, which needs to be well aerated and oxygenated, but which does not need to have biological filtration, since you will be performing 100% water changes daily throughout the treatment period.

If the seahorse is still eating, you could consider administering the Diamox orally via feeder shrimp that have been injected with a solution of the Diamox, Martin, in which case you could safely treat the seahorse in the main tank providing you are able to assure that the healthy seahorses won’t ingest the medicated Mysis or feeder shrimp. Giving the Diamox orally is very effective when treating tail bubbles or subcutaneous emphysema, and is sometimes helpful for treating chronic pouch emphysema as well, although pouch emphysema is best addressed by performing a medicated pouch flushes, in my opinion.

Also, Martin, you should be aware that the acetazolamide is typically available in 250 mg tablets, but it is a prescription drug and it can often be difficult for the home hobbyist to obtain.

As you know, the acetazolamide (brand name Diamox) can be administered in a number of different ways, and the best method of administration will vary depending on the form of gas bubble syndrome you are treating. Each of these different techniques for administering the Diamox requires a different amount of the medication. For example, chronic pouch emphysema is best treated by administering a Diamox pouch flush, after first evacuating any air bubbles from the seahorse’s marsupium. This method only requires one 250 mg Diamox tablet per pouch flush. Many times one pouch flush is all that is needed to resolve the problem, but stubborn cases may require two or three pouch flushes to be performed before the condition returns to normal.

Likewise, 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, Martin.

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:
in any
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.

Finally, Martin, the acetazolamide can also be administered in the form of pouch flushes, which is the most effective method of treatment when dealing with male seahorses that have developed chronic pouch emphysema.

The amount of the Diamox you will need to use to perform the medicated solution for flushing the pouch depends on the severity of the problem, Martin. In relatively mild cases, you need to dissolve 62.5 mg of Diamox (i.e., 1/4 of a 250 mg Diamox tablet or 1/2 of a 125 mg Diamox tablet) in 1 cup (~237 mL) of clean saltwater to prepare the solution.

However, in severe cases where the chronic pouch emphysema is long-standing, it is appropriate to use twice as much of the Diamox when preparing the pouch flush solution. So in a stubborn case of chronic pouch emphysema, you would need to dissolve 125 mg of Diamox (i.e., 1/2 of a 250 mg Diamox tablet or 1 entire 125 mg Diamox tablet) in a cup of clean saltwater to prepare a pouch flush solution with the proper concentration of the medication.

So if you are dealing with a mild case of pouch emphysema, you will want to prepare the pouch flush solution by dissolving 62.5 mg of Diamox in 1 cup of saltwater. Here’s how to proceed:

If you have the 250 mg Diamox tablets, break one of the tablets in half, and then cut one of the halves into two equal pieces. That will provide you with approximately 1/4 of a 250 mg tablet, which is equivalent to ~62.5 mg of Diamox, Martin.

(Likewise, if you have the 125 mg Diamox tablets, simply break one of the tablets in half, and that will give you approximately 62.5 mg of Diamox with which to prepare the pouch flush solution.)

Next, pulverize the 62.5 mg piece of Diamox, crushing it into a fine power, and mix it thoroughly with 1 cup of clean saltwater taken from your seahorse tank. (Some people like to use a blender to mix the Diamox with the saltwater so that it dissolves better.) I like to use saltwater taken from the seahorse setup when mixing the pouch flush solution, Martin, because that assures that the saltwater will have the same pH, temperature, and specific gravity as the seahorse is accustomed to, so that it will not be a shock to his system when it is injected into his pouch.

Now that you have prepared the Diamox solution for the pouch flush, let it sit for a few minutes before you fill the syringe. You will notice that some fine particles settle out of the liquid onto the bottom of the cup. That’s because the Diamox is not 100% soluble in saltwater, so there is always some undissolved residue.

Once the Diamox solution has had a chance to settle, suck up some the solution in the syringe (avoiding the undissolved residue at the bottom), and then hold the syringe upside down and depress the plunger slightly in order to expel a little of the solution, thereby eliminating any air that may be trapped in the barrel of the syringe. Leave about 0.5 mL of the Diamox solution in the syringe for the pouch flush.

Now you are ready to perform the Diamox pouch flush. First release any air that may be trapped in the male’s pouch using whatever technique is easiest for you, and then insert the cannula into the aperture of the pouch and slowly inject the solution into the pony’s pouch.

To provide you with additional guidance, Martin, here are the instructions from Keith Gentry explaining how to administer a Diamox pouch flush when treating a severe case of chronic pouch emphysema:

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 0.5ml 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 apparent side effects.

And here is another summary of the recommended procedure for administering the Diamox pouch flush when dealing with a mild case of recurring pouch emphysema, Martin:

Diamox Pouch Flush Instructions

ACETAZOLAMIDE (pouch flush) Dosage and Preparation Instructions
Active Ingredient: Acetazolamide
Indication: persistent and recurring pouch emphysema
Brand Name: Diamox
Dose at 0.5mL of a 62.5mg/cup solution
Supplies: narrow gauge irrigating cannula or narrow gauge IV catheter sleeve, 0.5 or 1mL syringe without needle

• Mix 62.5mg of Diamox (1/4 of a 250mg tablet) with 1 cup (approx. 237mL) of marine water with specific gravity, pH, and temperture matching that of the aquarium.
• Let the mixture settle.
• Fill the syringe with about 0.5mL of the solution, avoiding the residue that has settled to the bottom of the container.
• Hold the seahorse according to the procedure for pouch evacuations. Insert the catheter sleeve slowly and gently a small way into the pouch opening.
• Inject the solution slowly into the seahorse’s pouch. Leave the solution in the pouch.

Okay, Martin, that’s the rundown on the recommended Diamox pouch flush procedures. Just remember that you must first evacuate any gas trapped within the pouch before you perform the medicated pouch flush, and everything should go smoothly.

In stubborn cases, you may indeed need to repeat the medicated pouch flush more than once, so if you do not notice any significant improvement in the stallion’s condition in the next two days, don’t hesitate to repeat the procedure.

After you perform the pouch flush, the heavily vascularized lining of the pouch will gradually absorb the medication, so you need to wait at least a couple of days to determine if the Diamox pouch flush will have the desired effect. In severe or long-standing cases of chronic recurring pouch emphysema, it is often recommended that you repeat the Diamox pouch flush three times in succession (waiting two days after the first pouch flush and then performing a second Diamox pouch flush, and then waiting two more days before performing the third and final Diamox pouch flush) in order to resolve the problem once and for all.

For best results, it is customary to administer antibiotics in conjunction with the Diamox pouch flush(es), Martin. This is done as a precaution in order to help prevent any secondary infections resulting from the procedure. As long as the seahorse is still eating, the easiest and most effective way to accomplish this is to administer the antibiotics to the seahorse orally while he remains in the main tank, amid familiar surroundings, where he is the most comfortable.

Best of luck resolving your stallion’s problem with GBS, Martin.

Pete Giwojna, Ocean Rider Tech Support

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