how to express finding something is rarely got a hope?

[sky_wxt]

Hello there,I'm here to ask native Americans to do me a favor.

Think about this situation,that if you are looking for something which is really hard to find,
what idiom would you use to express?(Example,Look for a needle in a haystack,or something like that.
Please tell me ,thanks very much!

----From a Chinese english learner.

[Grumpy]

I think that the lack of any replies to you so far is a good indication that there aren't any commonly used expressions for this situation, other that the "needle in the haystack" example you quoted. I certainly can't think of one....

Incidentally, you asked "Native Americans" for help. I understand that that term refers to the original inhabitants of the Americas [who used to be called "Red Indians"], as opposed to those who settled there later. Unless you are looking for words and phrases used exclusively in so-called "American English", it's best to seek help from "Native English Speakers" - such as the British!

[MartinEnglish]

You've got a snowball's chance in hell of finding it?