I meant something you see on a tile floor. As for a fireball, I'd go with something flat-edged and not too realistic or detailed looking. Something like this:
But still, I think it looks tacky with that background color and something that 2D might not look right with that 3D-ish looking render.
If you want to change the color, all you need to do is play around with is hue/saturation (ctrl+U on CS2). Here's an example. I did a quick mock-up of your gray background and changed its color with the hue/saturation and some brightness changes as well as some brush strokes:
Forgive the text. XD As you can see, you can make the background totally different looking than what it started with without even doing much but tweak a few things.
