Wow... am not going to read all the hissy fits, but as said it all depends on the fish. Not to mention how much filtration and water changes you are going to do. (IE you can go for the Jap sardine can type tank if you really like that look. Just means a ton of work to keep your fish happy.)
I tend to have ~25 haps/peacocks in my 125. But well it changes day to day... And well it is impossible for me to stop buying new fish so I end up getting more tanks and moving fish around. (Mbuna well they just keep breeding so I can't tell you how many are in those tanks... say the equivalent of about 50 adults).
So in other words there is never any magic number... For tanks that size I would suggest you pick what fish you really want, get them keep them for a month or so, see how easily water parameters stay good and if you feel you want more and things are all looking good go ahead and add some more. Just remember that these fish grow too.
I tend to have ~25 haps/peacocks in my 125. But well it changes day to day... And well it is impossible for me to stop buying new fish so I end up getting more tanks and moving fish around. (Mbuna well they just keep breeding so I can't tell you how many are in those tanks... say the equivalent of about 50 adults).
So in other words there is never any magic number... For tanks that size I would suggest you pick what fish you really want, get them keep them for a month or so, see how easily water parameters stay good and if you feel you want more and things are all looking good go ahead and add some more. Just remember that these fish grow too.