The kioslave fish:/ enables you to access remote files through ssh, even if sftp is not installed on the remote host. It’s much more convenient than its cousin sftp:/, e.g. because dolphin remembers file associations etc.

Unfortunately, fish:/ requires perl. It copies a perl script to the remote host and executes it there. So if you run into an error like

Could not enter folder fish://root@HOST/root

when you try to point konqueror or dolphin to fish://root@HOST, the culprit could simply be a missing perl package on the remote host. Installing perl-URI should suffice:

# yum install perl-URI

For further debugging of the fish:/ kioslave, have a look at http://techbase.kde.org/Development/Tutorials/Debugging/Debugging_IOSlaves/Debugging_kio_fish