hey cory get rid of some of those mollies.as it stands 20 mollies in a 29gal.is way overstocked.of all the live bearing fish mollies are prehaps the most greedy hungry messy fish.they also grow pretty big compared to guppys,platys and swordtails.that and the given fact that they reproduce very quckly you will soon have a large problem on your hands.you personaly should add salt to your mollie tank,for a few reasons 1 mollies are often found in brackish enviroments,2 mollies have less health problems when kept in a salted enviroment,presumably because they use the extra minerals and calcium to develop bone and fin.3 mollies osmoregulatory systems are more like a saltwater fish than a freshwater fish.i'm not pulling this out of my head either.i read all of this in the dec/jan issue of tfh i can't remember which one exactly.if you choose to get some salt use a good marine salt not aquarium salt.and get a hydrometer too.i can't tell you what the reading should be off hand so we'll get to that later.i don't personal suggest putting guppys with mollies because they will outcompete the guppys for food so you will be overfeeding all the time to make sure the guppys are eating.i hope this helps.if you have more qusetions just ask.