Right so, my cycles done and im about to start adding fish.
The way im going to do it is add 2 per week until im done
And keep testing and changing water when needed until the bacteria colonizes to cope with the extra fish waste
Sound good?
Sounds alright to me but you might like to consider leaving it for a few weeks and then adding your fish with a bit more confidence and here is why:
There are a lot of misconceptions about how populations grow until limited by resources, bacteria populations in filters are no different.
It is often assumed that the population grows until it is consuming all the waste (ammonia/nitrite) and then stops growing. Becuase peopl believe that they also think that adding more fish will mean that the population has to grow before the waste can be processed. This is only true in a tank that has literally just finished cycling and here is why.
Give a population (of any animal plant or bacteria) a daily source of food and it will grow, eventually a significant threshold (call it T1) is reached when the food can be consumed as fast as it is being supplied, this is when cycling is considered complete as it is the first time all the waste is being processed,
but the population will not stop growing at this point. It will carry on growing at a gradually diminishing rate with the death rate rising and the birth rate falling until a balance is reached where births equals deaths, at this point the population is much larger than at T1 so if you throw in a bit more waste it will be consumed straight away no problem at all so adding more fish will not necessarily cause a mini cycle or indeed any measurable consequence at all except that the death rate in your filter goes down and the birth rate goes up until a new balance is reached.
This is not a license to just throw in more fish; for example if the tank has only just cycled you are still at T1 or if the bacteria don't have the space to live, ie your filter is too small or has poor/too little media this will limit the bacterial population, it is also posible add so many new fish that you overwhelm the bacteria. You still have to think about what you are doing but don't assume that adding fish will always cause a spike as usually it won't show any reaction at all and the above analysis of population balance demonstrates why.
If you doubt this logic imagine a typical family in the developed world and how much food comes in in the weekly shopping, now imagine adding people to the household (without chaging the weekly food shop) until everyone in the house is literally living on the edge of starvation, you probably now have 20 or 30 skinny unhappy people where you had 4 before. Now imagine what happens when you drop an extra rump steak and chips on the kitchen table, doesn't sit around polluting the place for long does it?
