The exact proverb is "There's as good fish in the sea as ever came out of it," though we usually say the shorter version. The traditional time to say this is when a friend has been dumped or otherwise disappointed in love. The basic meaning is that the thing (or person) you have lost is in no way unique, and you can easily get another one just as good or better. It is also possible to say this if someone has lost a job, and you feel they can easily get another one.
Of course it's rather heartless to say this to someone who has just had a painful break-up! It's a light-hearted saying and would expect a light-hearted response (as from one girl who had just been abandoned by her wealthy lover: "Yes, but he was a GOLDfish.")
Of course it's rather heartless to say this to someone who has just had a painful break-up! It's a light-hearted saying and would expect a light-hearted response (as from one girl who had just been abandoned by her wealthy lover: "Yes, but he was a GOLDfish.")