Blue Rams or Rainbows would be more appropriate for a 30 gallon tank. Especially the blue rams. If you go that route though make sure you realize that all the good advice people gave in this thread is worthless in regards to those fish as they are not Africans (Central & South America). Rainbows will generally do well with any tap water (treated of course) as they are not too picky on hardness or PH.
Blue Rams on the other hand are not hardy to begin with but generally need a fairly low PH and soft water to get any sort of longevity. Again they may be fine with your tap water, but if you have hard water or high PH water I would avoid them.