so far so good just make sure the silver dollars aren't big enough to swallow the neons. silvers are herbavores but it could be a concern. maybe a nice pleco with that size of a tank he would be very happy. Have you seen some of the cycling advice?
check out the profiles. when I first saw this site I must have spent hours looking for the fish I wanted and what fish would go with them. I try to plan a tank out with all levels of the tank being used. Some fish live in the top, middle or bottom. do your research and see what works for your vision. have fun.