Hey man, literally any RGB fixture can be used in pixels. If no fixture profile appears in the list when you open Pixels, it may just mean that there is no fixture profile for it. You can request a pixels profile be made for you elsewhere on this forum, otherwise it is very easy to create your own.
https://www.youtube.com/watch?v=l-rizeycH3k^This video shows you how to add a fixture. Skip to about 1:49
https://www.youtube.com/watch?v=LSPp2hf63JI^And this video shows you how to use an ordinary par can in pixels, also at about 1:49.
If you're still confused, i might upload a video later showing you how to do what you're asking. It's very easy once you know your way around pixels. I suggest to any user of this software to get familiar with creating your own fixture profiles as it is extremely easy and will open up a vast amount of opportunities for you in terms of creative use of the software.
Regards,
Tim H