I'm using Tixati on Fedora 21 (with GNOME 3.14), and Tixati doesn't display an icon on the bottom notification bar. Tixati does put itself down there though, but it uses a blank icon (so if I put my cursor in the blank area, I can find Tixati).

Anyone know how I might be able to fix this?

Since you can click on the blank and find tixati, might I suggest it is an operating system error not displaying an icon. You should likely explore the operating system for not displaying the icon.

I'm unsure of how to get icons to display; but it seems other 3rd-party programs (Transmission and Google Chrome) can display icons fine. Vuze also didn't seem to show an icon though, so there may be some kind of common incompatibility/breakage somewhere.

It seems to work fine in Fedora 22 Alpha, were they removed the old notification bar and added a "tray" on the lower left of the screen. On the other end it looks like tixati still uses xembed instead of libappindicator, so there is no icon shown in plasma 5.