Both wide angle lenses, fisheye lenses, and wide angle lenses have larger FOVs and shorter focal lengths than normal optical lens assemblies.
For regular wide angle lenses, the focal lengths are typically greater than 25mm, and the FOVs are smaller than 90 degrees. While the fisheye lenses and super wide angle lenses have ultra-wide FOVs above 90 degrees and even greater than 180 degrees and very short focal lengths between 16-25mm or less than 16mm.
There’s no definite border line of focal length and field of view to differentiate super wide lenses and fisheye lenses.
In general, there are two major differences between fisheye lenses and super wide angle lenses. The first difference is that the front lens element fisheye lenses protrude outward like the real eye of a fish. The second difference is that fisheye lenses do not aim to provide rectilinear images, but are oriented for capturing a maximized range of areas, producing images with a much stronger curvilinear nature and significant barrel distortions which requires software correction (The image close to the edge is compressed compared to the center of the image, and the straight lines in the image will be more skewed). In comparison, super wide angle lenses tend to offer a more realistic aspect ratio.