Uninstall/Delete fishfish shell or upgrade to v2

$ fish -v

just to check the version if is <2
delete these files
/usr/local/share/fish/
/usr/local/ect/fish/
/usr/local/bin/fish*
~/.config/fish
check if everything is clean
fish -v
should output
-bash: fish: command not found

use homebrew http://mxcl.github.com/homebrew/
try this recipe
brew tap edc/homebrew-fishfish
if it says fatal error so you have already the recipe
brew install fishfish
wait it to finish