That’s good news, sir! I’m glad to hear she bounced back so quickly. No doubt she was a little stressed out from the ammonia spike and being transferred into a strange new environment. She should be none the worse for wear now that you’ve got your ammonia levels back down to zero.
I would feed your seahorses sparingly for the next few days to give your biofilter time to adjust to the heavier bioload, which should help prevent any further spikes in your ammonia or nitrite levels. Other than that, it sounds like you’ve got everything back on track again.
Best wishes with all of your fishes, Seagazer!