Sounds like you did a fine job of cutting that forest of Aiptasia rock anemones down to size, sir! (Joe’s Juice is also my preferred weapon of choice for injecting Aiptasia.) Well done! Get a couple of good-sized peppermint shrimp (Lysmata wurdemanni) in there now and you should have no more worries with regard to Aiptasia. That’s one potential hazard under control, which should pay nice dividends for your seahorse enclosure in the long run.
I’m sorry to hear the freshwater dip did not have the desired results. But I still think treating the female H. reidi with hyposalinity and Furan 2 is your best bet for a good outcome. Reducing the salinity and gradually lowering the water temperature in the hospital tank will conserve her bodily resources and slow down her metabolism, buying the time you need to line up some choice live foods and get her eating again.
A basic hospital tank can be set up pretty quickly and easily, Don. A bare-bottomed, 10-gallon aquarium with plenty of hitching posts will suffice for a Quarantine Tank (QT). Ideally, the hospital tank should have one or more foam filters for biofiltration along with a small external filter, which can easily be removed from the tank during treatment but which can hold activated carbon or polyfilter pads when it’s time to pull the meds out. It’s important for the hospital ward to include enough hitching posts so that the seahorse won’t feel vulnerable or exposed during treatment. Aquarium safe, inert plastic plants or homemade hitching posts fashioned from polypropylene rope or twine that has been unraveled and anchored at one end are excellent for a hospital tank. No aquarium reflector is necessary. Ambient room light will suffice. (Bright lights can breakdown and inactivate certain medications and seahorses are more comfortable and feel more secure under relatively dim lighting.)
So just a bare 10-gallon tank with hitching posts is all you need for your hospital ward. No heater. No reflector. No lights. No substrate. You can even do without the sponge filters or external filter in your case, just adding a couple of airstones to provide surface agitation and oxygenation. That’s it.
In a pinch, a clean 5-gallon plastic bucket (new and unused, NOT an old scrub bucket!) can serve as a makeshift hospital tank. It should be aerated and equipped with hitching posts and perhaps a heater, but nothing else. This makes a useful substitute when the Quarantine Tank is occupied or in use and a seahorse needs treatment.
Stay on top of water quality in the hospital tank/bucket with water changes (using hyposalinity water if you will be administering OST) as often as needed during treatment, and redose with the medication according to directions after each water change.
If you’re having trouble obtaining suitable live foods, Don, you can always consider tube feeding the affected seahorse. Force feeding can save a seahorse’s life in an emergency, but it’s best reserved as a last resort. It’s not a long-term solution, but rather a stopgap measure to provide desperately needed nutritional support for a seahorse when all else fails. If the tube feeding has to be continued for more than two or three days, it is apt to do more harm than good. But it could buy you a little more time to line up choice live foods.
Tube feeding is appropriate when a seahorse has gone without eating for a prolonged period and has exhausted its energy reserves. This can happen when a seahorse is beset with internal parasites and stops eating, or perhaps when a seahorse is undergoing extended treatment with a medication that suppresses the appetite. And, of course, it is very common — perhaps even the rule — in wild-caught seahorses that have run the gauntlet from collector to wholesaler to retailer before finally reaching the hobbyist (Lidster, 1999). In such cases, tube feeding can help strengthen the seahorse and keep it going until it has a chance to recover and resume feeding on its own.
Just let me know if you want to try hyposalinity in the hospital tank, and if you feel tube feeding is appropriate in your case, Don, and I will send you explicit directions complaining exactly how to proceed in detail.
Best of luck restoring your female H. reidi’s appetite, sir!