It sounds like you are doing everything possible to help Zoe. It was a good thought to include a nice big clump of Chaetomorpha turf algae in the treatment tank so that she could snap up live ‘pods if she was so inclined and able to get them, and hopefully she will have an interest in the Snicking Shrimp when they arrive.
If she is able to eat the snicking shrimp, then you could consider returning her to the main tank and administering the Diamox orally by injecting it into the Snicking Shrimp. But otherwise I would continue the prolonged immersion in Diamox for as long as it takes to reduce the abdominal swelling and return her to normal buoyancy.
Internal Gas Bubble Syndrome (GBS) is is the most dangerous form of this affliction because any of the internal organs in the abdomen can be affected by the gas emboli that form in the seahorse’s blood and tissue, yet there are no outward indications of trouble at first, making it difficult to detect the problem until the condition is well advanced and serious damage has been done. The gas emboli occlude vessels and capillaries, thus restricting the blood flow to the affected area, which is what makes the internal form of GBS so insidious — irreversible damage can be done to vital organs or organ systems before sufficient excess gas builds up within the coelomic cavity or gas bladder to cause positive buoyancy and alert their keeper to the problem.
When treating internal GBS, the outcome often depends on which internal organs were involved and how soon the problem is detected. In my experience, the prognosis and chances for a successful outcome are much better when treatment is begun while the seahorse is still eating. Unfortunately, that can be difficult to accomplish when you’re dealing with Internal GBS because the seahorse remains largely asymptomatic until it becomes bloated and begins to float.
It’s possible that gas emboli have also migrated to the seahorse’s tail via the dorsal aorta and that that’s why she is no longer using her tail to hitch or grasp onto things right now. Now it’s just a matter of seeing if the problem was detected early enough for the Diamox to help and reduce the swelling and other symptoms.
Best of luck treating this difficult problem, Pat. Here’s hoping that the Diamox begins to have an effect and reverse some of her symptoms and that she has an interest in eating the live white shrimp when they arrive.