How can I repair my fish tape?
Even spring steel will hold a bend if you take it far enough. The only question is whether it snaps before you get an acute enough angle.
I'd snip off the damaged length, then drop the new end in a vice, but a fair bit longer than the final hook should be. Slowly hammer it over until you're at 90 degrees, then take it out and mount it sideways in the vice. While holding the long hook down as far as you can by hand, continue to hammer the bend tighter. Once it's to about 135 degrees you can probably take it out of the vice and rest it on top for the final bending. Then trim the hook to length.
If you find that the metal wants to snap off or tear you may have to heat it with a torch and work it hot, or maybe ask a friend to weld a hook on it. I'm no blacksmith, though, and can't offer much advice there.