Yes, fish can see shapes.
Fish vision is adapted to their aquatic environment. Their lenses are round and protrude through the iris, enabling a wide field of view and the ability to bend light effectively underwater. While fish vision may differ from human vision in some aspects, such as color perception in certain species, their eyes are capable of distinguishing shapes. The referenced YouTube video extract confirms that the lenses in fish eyes help them see by bending light. This bending of light allows the fish to form an image that their brain can then process, including the identification of shapes.
