I used Krylon indoor/outdoor Satin Black to paint both the back wall and the right end wall of the tank. I'm hoping to cover the right hand wall with my bark piece, so didn't want the back side of that visible on the end. I started by setting the tank on cardboard, taping off the plastic rims, and covering parts I didn't want painted with newspaper (sorry about the quality of this shot, didn't realize how hard it is to take and infocus picture of a painted tank, and I only took the one);
The final coat;
I layered quite a few coats on in order to completely cover the glass, but was pleasently surprised by how easily it covered. Being patient and giving plenty of time between coats was key, to getting a nice smooth finish.
And the final product;
If you try this on your own, the only other advice I would give is be careful in taping to keep the tape completely off the glass and when removing the tape be very careful as it may peal the paint. I lost a little around the upper end and then had a really hard time getting it to recover - unfortunately I got a bit of a run on that end as a result.
Now that its painted, I do notice that the paint really makes the scratches and dirtiness really stand out. I don't think I'd paint another one unless it was brand new. I really want to jump in and get the bulkheads back in place and start scaping, but I'm sure I'd mess something up, so I'm going to make myself walk away and wait till later in the weekend or Monday before I do any more.