To dream of an ice cube melting suggests a time limit on a current situation that you may be feeling pressure to complete.
A lone ice cube may suggest that you are not as interested in an idea as you once were but that you may feel shy in expressing your feeling in fear of upsetting another. Many ice cubes rattling around speaks of an irritating person trying to get your attention, keep your cool as they are likely to fade away fairly rapidly.
[1]A melting piece of ice may point to the melting away of your fears.
An ice cube may also mention emotional coldness as in a hard hearted individual.
[2]