Dude, I tried to install Koala on Fedora and Arch. Didn’t work either time. I know for sure that on Arch… It’s not an official package… Which could be the problem.
I just came to the conclusion that I didn’t need it. I wanted it for mass photo compression but Linux can do that natively with a simple script. Bash, Python, Perl… Pick your poison. Anything you want koala for can probably be done in the terminal.