Panda corys are not good for a newly setup tank and definatly not a cycling one as they require constant good water conditions which are hard to achieve in new setups.
Livebearers do not need salt to be healthy, although mollys can either be raised in brackish/salty conditions or freshwater and ones raised in brackish conditions do not always fair well in freshwater setups- all other common livebearers are not brackish fish at all and salt should only be used as medical treatment for them, so platys, swordtails and guppys are perfect for a freshwater setup but if you are going for mixed gender groups you need to get the gender ratios correct for the group to be stress-free as posible and also you need to be prepared for the large amounts of fry they produce.
If this is a new tank you have, i wouldn't advice panda corys as they will most likely die off- they are hard to keep alive even in matured tanks at times due to being very sensitive fish- personally i would advise you go for a more hardier cory type like albino, bronze or pepperred corys.
All corys need their diet substituted with catfish pelets and/or algae wafers, they also prefer very fine gravel or sand as due to being filter feeders, it allows them to filter through the substrate and feed easier and it will also help prevent them from getting bacterial infections/eroded barbels/whiskers; they also prefer to be in groups of at least 4 due to being very sociable shoaling fish.
Corys are very peaceful fish and can go with many types of fish, if you are still intested in livebearers like platys, guppys or swordtails these will make good companions for your corys, what fish are you interested in?
