If you want a fisheye, get a many brand fisheye (rokinon,opteka,samyang,bower) I suggest the opteka 6.5 or rokinon 8mm CANON mount. Do not get one that attaches to the kit lense.
Whenever you buy a lens, it will tell you the zoom length ex: 50-250, 50, 70-300 and that's how much it zooms...