No, fish eyes are not generally considered hard.
While the texture can vary depending on the species and preparation, the outer layer of a fish eyeball is typically described as soft and gooey. Some chefs compare the experience of eating a fish eyeball to eating a raw oyster. The center of the eye may contain a firmer, somewhat crunchy, wafer-like texture. So, while not "hard" throughout, there might be a textural contrast between the outer layer and the center.
