Quote Originally Posted by mtbbrian
I don't know if fade is the correct term, I think it will show signs of discoloration, assuming it survives being exposed to light that long.
But you MIGHT, be able to fix and wash it again and it SHOULD be OK.
It's been a while since I have developed any film so I don't completely remember.
Brian
If it's not fixed properly, it will be cloudy. In this case, you can refix it later. I don't know how much later you can go, but I've heard of people refixing after weeks or a month. Assuming it was in the fixer for at least a minute or two, exposure to light shouldn't be a problem...unless you try to develop it again.

The problem The Wombat was describing sounds more like incomplete washing. Fixer is acidic and if it's not properly washed out it will slowly cause the plastic film base to deteriorate and become discolored, which can not be reversed.