I recently aquired a Nikon fish eye lens for my nickkormat slr. I have never used this type of lens before and was surprised to find that it does not fit onto the camera. Is there some sort of adapter that I need?

Here you find Russian Zenitar and Peleng fisheye lenses with adapters for Nikon cameras:

http://www.kremlinoptics.com/catalog/nikon_lenses.html

Very low prices!