To clarify my point, this is one of the contingencies I specifically mentioned my theory did not account for. My assumption was that most people are not either so confident (or overconfident I'd argue) or foolish enough to fill a tank with fish in one fell swoop. If this is your plan, I do understand the argument for a "robust cycle". You will need a large enough population of bacteria to handle this bioload from the get go, and if you don't give them enough of an energy source from the beginning, the tank will more than likely not be ready. In this particular case, I would imagine the addition of an external ammonia source would be necessary. I think it's still quite a bit of a risk, though. But I guess if you can't decide what you should do, a cocktail shrimp or two probably isn't going to do anything more harmful than stink a bit and perhaps look kind of nasty for awhile.
The reason for a robust cycle may vary a bit. I'd agree that stocking as quickly as possible after a robust cycle takes some nerve and a lot of experience, and I definitely do not recommend that newbies do so. Apart from the nerve part, there is real issue with disease control, as I have said many times.
Instead of stocking as quickly as possible as I do after a cycle, one can stock rather fast, say half to 2/3 of the planned bioload in the five weeks after the cycle. Having a robust cycle definitely is needed. When you are at 8 units of bioload say at the end of fifth week, adding more livestock later may not be a big deal. Even long after the cycle, going from 8 to 9 or even 8 to 10 is much better than going from 1 to 2, or 5 to 10.
The alternative of not having a robust cycle (actually not realizing the correct way to cycle) is to stock slowly. If you add one unit of bioload and than wait 3 months before you add another one, you would be re-cycling with livestock. There is a large problem with is approach. It is to accept that re-cycling as you add livestock is necessary or acceptable. If is not, and ammonia at even quite sub-lethal level is not good for fish for and at any time.
There is a very easy way to add fish slowly and still avoid all re-cycling. You can cycle robustly the initial medium, and then you cycle separately. It is very easy.
This is the simpliest way to avoid re-cycling when you want to stock slowly, as newbies should.
1. At about the same time you cycle the initial medium. Get a round 5 gal bucket.
2. Fill it to two to three inches of crushed coral or LR rubble the size of pea to grapes.
3. Fill the bucket to 2/3 filled with DT water from WC.
4. Use a small powerhead to circulate the water. The roundness of the bucket is great in creating a nice circular current. Have the powerhead cling to the wall of the bucket.
5. Continually feed the bucket with fish food, imagining that there are a couple of medium sized fish in the bucket. Keep mock feeding of the imaginary fish.
6. When it comes time to add new fish. Use some of the gravel in the bucket to bump up the nitrification in the DT, You can put it in a nylon sack and let return water run over it. You can even rinse the cycled medium with tank water to rid it of any dirty cycling water.
7, replenish the medium in the bucket
8. In the coming weeks, gradually withdraw the added medium from the DT 10-15% bi-weekly.
Re-cycling is totally preventable. No fish should be exposed to any ammonia if the aquarist can prevent it. New tank syndrome for fish should not be a factor anymore.
BTW, I always stock as fast as I can for three reasons.
1. sometimes incompatibility issues are reduced.
2. It facilitates QT. I QT for at least eight weeks. Adding just ten fish in a 125 gal will not take 80 weeks of QT, generally about 10-12 weeks.
3. Better bargaining power with LFS.