Wow! Good work coming up with a much deeper homemade decompression chamber and lining up some of the difficult to obtain Diamox on such short notice. Since you only have six 250 mg tablets of the Diamox and the treatment is more effective when the Diamox is combined with a good antibiotic, I would recommend reserving your precious Diamox tablets until you have transferred the seahorse to your hospital tank, and then adding a good antibiotic to the hospital tank at the same time. That will allow you to treat the seahorse for six consecutive days with your limited supply of Diamox, and you will probably need to maintain the treatments for at least that long when you are dealing with internal gas bubble disease, which is by far the most difficult form of GBD to resolve.
So, for now, let’s rely on your homemade decompression chamber to do the job. The first thing you need to do, seahorsegirl, is to aerate your decompression chamber to keep the level of dissolved oxygen from being depleted. As you know, gas exchange takes place at the air/water interface, and there is very little surface area to the tall 7.5 foot cylinder you are using as your decompression chamber. That means that it will be ineffective using an airstone or a powerhead to try to oxygenate the water column in the cylinder.
I would recommend using hydrogen peroxide to aerate the decompression chamber, as explained below. By my calculations, your homemade decompression chamber holds about 11 gallons of water. The volume of the decompression chamber is 2547 in.³ and dividing that volume by a figure of 231 will convert the volume in cubic inches into gallons of water, which comes out at ~11 gallons. But since the decompression chamber is not filled all of the way to the top, and the critter keeper the seahorse is in also displaces a bit of the water, let’s figure the water volume of the decompression chamber at 10 gallons to be on the safe side when dosing it with the hydrogen peroxide, seahorsegirl. You can use 3% hydrogen peroxide – which is the concentration of the household hydrogen peroxide you might purchase at the drugstore or pharmacy – in order to aerate your homemade decompression chamber.
Dosing tank with H202 to boost oxygen levels
There is also another trick you can consider for raising the dissolved oxygen level in your aquarium quickly by adding a small amount of ordinary hydrogen peroxide (H202) at the right concentration to your aquarium. Hydrogen peroxide can be use as a treatment of acute oxygen insufficiency at a dose of 0.25 ml of a 3% H2O2 solution per litre of water, which is equivalent to adding 1 ml of a 3% hydrogen peroxide solution per gallon of water.
Remember to allow for the amount of water that is displaced by the aquarium substrate and decorations when calculating how many milliliters of a 3% hydrogen peroxide solution to add to your aquarium. Be careful not to exceed the recommended dosage since adding too much of the hydrogen peroxide can be harmful. This is a one time emergency procedure for use in a crisis situation — do not add any additional hydrogen peroxide to the aquarium after the first dose.
Contrary to popular belief, in water with relatively low organic content, the concentration of Hydrogen peroxide does not decrease significantly. Of course, any increase in organic loading will change this factor, but the bottom line is that Hydrogen peroxide does not break down as quickly as some may think. Water changes are required after treatment.
In other words, seahorsegirl, I would recommend adding 10 drops – but no more than 10 drops – of the 3% hydrogen peroxide solution that you may have in your medicine cabinet at home right now, or that you can obtain from your local drugstore to your homemade decompression chamber. Please do so immediately! That will assure that your very tall homemade decompression chamber has an adequate level of dissolved oxygen for your seahorse despite the extremely limited surface area at the top of the PVC pipe.
It’s very difficult to predict how long it may take for the homemade decompression chamber to have the desired effect, seahorsegirl, because it depends on so many factors: how severe the problem with internal GBD is, how long the seahorse has been affected by this problem, how deep the homemade decompression chamber is, and whether any of the internal organs of the seahorse have suffered irreparable damage in the interim. But since it’s been several days since your female has eaten, I would recommend very slowly raising her to the surface after 24 hours in your deeper decompression chamber to check on her progress. Be sure to raise the seahorse very methodically, in several stages, taking at least an hour to bring her all the way to the surface.
Once you have her up, I would recommend force-feeding your female by hand, which I think is your best option to see that she get some nutrition. If her positive buoyancy still isn’t resolved, she will have difficulty eating on her own, and force-feeding her as described below can buy you some more time:
By handfeeding in this case I mean holding one entire, intact (whole and unbroken) frozen Mysis that you have carefully thawed in your fingertips and then placing the tail of the Mysid directly in the mouth of the seahorse. Many times the seahorse will simply spit it out again, but often if you can insert the Mysis into her open mouth far enough, her feeding instincts will kick in and take over so that she slurps up the frozen Mysis almost reflexively. That’s a much less stressful and less invasive method of force feeding a seahorse that sometimes works well (especially if the seahorse is accustomed to being hand fed and doesn’t shy away from the aquarist). Force feeding the seahorse by hand sounds much more difficult than it actually is, and seahorses will often respond well to this method of feeding, Claire. Even the professional curators at the large public aquariums will use this technique when their highly prized (and very expensive) seadragons are experiencing problems with weak snick.
If her positive buoyancy has not responded, go ahead and quickly lower your female back to the bottom of the 7.5 foot tall decompression chamber for another day after you have fed her by hand as described above. You can repeat this procedure of very slowly raising and then rapidly lowering your female to the bottom of the decompression chamber again after she has had a chance to be hand fed each day for as long as necessary (although you only add the 10 drops of hydrogen peroxide to the cylinder on one occasion), seahorsegirl, but if it has not made a difference after 2-3 days, then it’s unlikely that a longer duration of pressurization will be helpful.
In that case, I would transfer your seahorse to a 10-gallon hospital tank and begin treating with Diamox, 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 Diamox 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.
While you are treating your female in the homemade decompression chamber, seahorsegirl, I would recommend lining up the good antibiotic that you can use together with the Diamox afterwards. Minocycline is the active ingredient in Maracyn-Two by Mardel Labs, and that is a medication that is readily available at many local pet shops and fish stores. Use the Maracyn-Two together with the Diamox when treating your female in the hospital tank.
Best of luck resolving this difficult situation and returning your female to normal again, seahorsegirl.