After nearly having a heart attack for each notification my Aqua Fish does I've decided to replace the sounds. Since I've been through a Nokia n900, n9, and Jolla OTH I've come to like being woken up gently - it's effective and doesn't jar me. The Aqua Fish notification sounds are in your face loud and abrasive.
I searched on the Internet for Jolla sounds even though I could have extracted them from my own phone. I found a download link in this forum thread - http://www.jollausers.com/2013/08/jollaringtone2/
Once downloaded I dropped them in the filesystem and went to Settings -> Utilities -> Refresh Media database. I could then choose the sounds in Settings -> Sounds and Feedback.
This is not how I wanted to do this. I wanted to copy the sounds to the /usr/share/sounds/intex-ringtones directory and edit the stereo.index file and have them show up in the Sounds and Feedback dropdown menus but it didn't work. If anyone knows how to change out the stock sounds please let me know.