possibly, i would start with 30 to 35 & see how that is. i think you may find 50 is achievable but it will be better to start off with a smaller number & work up particularly if you start with juvies. that tank will easily handle 60 juvies but as adults they may be too large, doing this will mean you can weed out numbers to get good male & female ratios. also keep in mind they won't be easy to catch in a tank of that size, i recommend a divider/s of some sort to reduce the area to catch them in.
what are you having as filtration, plenty of that will be needed for these numbers.