Ammonia recovery?

So, to start, yesterday I fed my yellow-tail damsel in my 10g Nano Reef and he was eating like crazy, swimming around a lot and in general very happy. Today I came home from work and he's swimming in place on the bottom and not looking very happy. Checked ammonia and it was present, but barely. I noticed my Blasto, which had been on it's last leg from a previous tank incident, looked completely dead. I immediately removed it and did a water change. Now ammonia is 0, nitrites are still 0, and nitrates are 0-5. Do you think my yellow-tail will bounce back? How long might recovery take?