Candles float because water density is higher than wax density, a physical particularity that makes them a such useful decorative resource!
For original table settings, you can put little floating candles in glass vases filled with water.
For outdoor parties in gardens provided with a pool, you may try candles with wind resistant wicks or hurricane candles designed to protect the flame from air draughts.
Did you know why candles in a pool tend to move to the borders instead of staying still? The answer is water’s surface tension, the same reason that prevents Water striders from submerging. Psst… Prop stylists often use fishing plumbs to make candles stay in place!