Is there such a thing as a thin (1/8 in. or smaller) snake, for fishing wire through tight places?

Yes-I have a Greenlee steel fish tape #438-10, tape size is 1/8" x .060". This appears to be a standard size tape.

I have a greenlee Stainless, Excellent. However, The "BEST" is the inside of Boat control cables. Hopefully there is a boat yard nearby.Bigger the boat the better.
Its Round, Small(maybe larger than pencil lead)and stainless.
Won't leave marks like like on old steel tape.
Luckily, the tight places are usually short.(less than 15 foot)