As Mr. Mojo said, your clown will not survive. I start my tank's with a piece of frozen cocktail shrimp. It takes up to 10 days for ammonia to show and it will start to go down around week two, but only slightly. IMHO ammonia doesn't start to really go down until 3 weeks. Once you read nitrites you're mid-to late cycle. I personally wouldn't add a fish until nitrites are zero and nitrates are being read consistently.
*stuff in a bottle is not a substitute for a full cycle
The tank was started well over 2 months ago now. While I do not think it’s a good way to cycle, I would not have said it won’t survive. Many people overestimate the lethality of ammonia.
In any case, maybe the op can now tell is what happened!