If you tested ammonia with an API test kit, it's pretty much worthless as those things will read ammonia on RO/DI water. Good rule of thumb for the future, if you're going to own an anemone invest in good test kits and have Cipro on hand. This should have been into a Ht starting treatment as soon as you found it like this along with a full gamut of water tests to see if something in your water caused it.