I'm gonna have to disagree completely. The only way your not harming the fish is if ur keeping ur levels at 0. Besides for nitrate of course. But during cycle ur parameters change so much that ur gonna stress the fish out regardless of if u thinl ur harming them or not. Its best to fishless cycle. Plus why add 1-2 fish at a time hoping ur biological filter keeps up. In a fishless cycle you can build a stronger biofilter in less time. Add all ur fish at once.
I'm not saying your wrong. But I disagree with you 100%
Okay, so lets flesh this argument out a little, if you are willing. We are both logical people, right?
You are incorrect about the 'keeping your levels at 0 or you are harming the fish' statement. I'm not sure where you read this, I know that some forums circulate this information but it's just not correct. Ammonia toxicity is dependent on both pH and temperature. What that essentially means is, it's not always in a toxic state to animals, and whether it is or isn't depends on a few factors.
There are charts readily available that show ammonia toxicity in relation to pH and temperature. Ammonia ionization (happens naturally in lower ph and temps) is something that the fabled Prime type water conditioners rely on.
Okay moving along. If you understand the nitrogen cycle then you'll understand what is going on in your tank. So there's no wild fluctuations or changes in parameters that are not already understood beforehand.
You are only giving the positive side to fishless cycling, there's some negatives also. If you enjoy searching around town for the 'right' kind of ammonia to dose. (The irony is living things everywhere are giving off ammonia in some form or fashion). If you are fine with staring at an empty tank for 3-4 weeks or more, then by all means, but it's not for me. Especially when fish-in cycling can be done safely and easily if you know what you are doing. Again, you are welcome to disagree, but a factual counterargument would be the most productive.
Also, you don't have to add 1-2 fish at a time and 'hope' the biofilter catches up. Heavily plant the tank, add some seeded media, and stock the fish. If you are wary, stock lightly and see how things go for a while before you add more. If you get good at this, you end up starting systems that need no more work than the standard weekly water change routine.
"Building a stronger biofilter" argument does not work either, simply because biofilters are dynamic. The nitrifying bacteria colony grows and shrinks based on the amount of resources available. So, even if you do dose 5ppm ammonia to make a massive biofilter, it's just going to eventually die back and shrink down to whatever size works with the amount of nitrogenous waste being produced.
Honestly, when people try to make the 'fish in cycling is cruel!' argument, I want to respond with 'fishless cycling is cruel to people', since everyone in the vicinity of the tank has to stare at emptiness and scratch their heads for a month or more because the person in charge thinks they are being humane.
It's cool not to understand something, we are all ever learning, but it's not cool for someone to villainize a methodology because it's not well understood by them yet.