6 is yet another "Rule-ofThumb" that we use; however, this # varies based on fish species and size, tank size, stock or crowding, cover, use of a dither fish, etc., etc., etc......
6 is simply a number of fish suggested to ensure that a schooling fish will not be too stressed or act too far out of its normal behavior to cause other issues such as eatting problems, skitishness, aggression, etc.
To top things off, each fish has its own personalilty (not the schoolers as much), however, each "school" develops their own temperment, and not any two are the same. In other words, 5 might work for you now, but a later restock, even in the same tank, may not behave the same until you get more. I have seen this happen in my own tanks enough.
6 is simply a number of fish suggested to ensure that a schooling fish will not be too stressed or act too far out of its normal behavior to cause other issues such as eatting problems, skitishness, aggression, etc.
To top things off, each fish has its own personalilty (not the schoolers as much), however, each "school" develops their own temperment, and not any two are the same. In other words, 5 might work for you now, but a later restock, even in the same tank, may not behave the same until you get more. I have seen this happen in my own tanks enough.