If a fishless cycle is done with ammonia nitrate does get high, which is why the water change is needed - more like 100% to get the water back to tap water levels.
If a fishless cycle is done with anything other than ammonia, there is no way to know how many bacteria have grown so fish must be added a few at a time, testing for ammonia and nitrite daily until it is certain they're both remaining at zero. After a week of zeros, another batch of fish can be added.
But back to your question - I would still do a water change to make sure everything is back to tap water levels before adding fish.
If a fishless cycle is done with anything other than ammonia, there is no way to know how many bacteria have grown so fish must be added a few at a time, testing for ammonia and nitrite daily until it is certain they're both remaining at zero. After a week of zeros, another batch of fish can be added.
But back to your question - I would still do a water change to make sure everything is back to tap water levels before adding fish.







