I was just curious as to how often i can buy and put fish in my tank. for example I herd you should only put 1 fish at a time but what if i'm trying to put a school or shoal of chromis?
just looking for a rule of thumb kind of thing. maybe 1 fish per week, 2 fish per week...so on.
thanks!
As for as handling ammonia from livestock is concerned, it all depends on how you cycled your tank (more precisely how you cycled the filtration medium intended for your tank).
If you had cycled your tank robustly using a source of ammonia that can achieve enough ammonia during the cycle, then within a window of about three weeks after the cycle at least, your tank should be able to handle the ammonia from a rather high bioload at once.
If you used the silly gradual method to "cycle", you will have to stock slowly. The need to stock slowly for concern over ammonia also means that your livestock is exposed to some low level of ammonia. This should be avoided if significant and possible. If you have just one unit of bioload, going to two unit will be significant. If you have 9 units of bioload, going to ten will not be a serious problem regardless. 1/2 vs 9/10.
Newbies should stock slowly for other reasons other than concern over ammonia for a "new" tank. I believe newbies should stock slowly mostly to learn the ropes in disease control.
It is easy even for newbies to make sure that at the end of a cycle, for at least three weeks, there is very dense and active nitrification bacteria to process all ammonia from livestock.
Later, long after the cycle, you can bump up the nitrification capacity of any tank to accomodate any sudden increase in bioload.
Sometimes sudden increase in bioload is unavoidable, such as in the stocking of a single very large fish into a tank that was cycled a year previously. One has to prepare in advance so that there is no re-cycling that won't be mini at all. Otherwise, that very large fish and its tankmates will go belly up.
If you had made preparation in advance, the rate of stocking of fish should be based on issues other than having enough nitrification bacteria.
Compatibility, disease control, etc are all factors, not nitrification, ideally.