the JVC GZ-HD7 has a 46mm lens filter diameter. Page 80. It has threads for mounting an add-on lens. Doing a search for "46mm fisheye" found some add-on lenses - but they are fairly expensive. Since 46mm lens diameter lenses or filters are not very common, a step up to something more common is possible.
Here's a 46mm-52mm step up
http://www.bhphotovideo.com/c/product/387499-REG/Cokin_CR4652_46_52mm_Step_Up_Ring_Lens.html
and a low end 52mm fisheye
http://www.bhphotovideo.com/c/product/699870-REG/Bower_VLB1658_VLB1658_0_16x_Ultra_Wide_Fisheye.html
Or you can step down
http://www.bhphotovideo.com/c/product/98893-http://www.bhphotovideo.com/c/product/809670-REG/Sensei_sdr4637_46_37mm_Step_Down_Ring.html
and a low-end fisheye...
http://www.bhphotovideo.com/c/product/699858-REG/Bower_VLB1637_0_16x_Ultra_Wide_Fisheye_Lens.html
Don't worry about the lens hood mounts you showed us - use the threads - they are visible in the following pics you posted
http://postimg.org/image/lxxl0wtur/ (near the thumb)
http://postimg.org/image/xkhp21h5v/ (at about the 1 o'clock position, reflecting)
Personally, I would suggest shooting the video with no add-on lens and using a fisheye filter in a decent video editor... Final Cut Pro X, Adobe Premiere and Sony Vegas are there usual suspects.

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