Fishye lens under £150?

[RedSpectrumPictures]

I use a canon 600d dslr, and was looking for a fisheye lens for under £150, that would be good for filming sport.
I currently use a 18-135mm lens, and I am getting the 50mm 1.8 (thanks for everyone on the forum who guided me on what lens to buy).

Can I get a fisheyeye that screws onto filter threads, or would I get one that is a whole new lens?

 

[tommyp]

Check out the samyang 8mm a little more than your budget but a good lens for pennies.