Fish do not have eyelids, with the exception of the shark. Eyelids are used to protect the eyes from dust and keep them moist; fish do not have these problems underwater, so there is no need for eyelids.
Although fish do not have eyelids, they can sleep. Some float, while others bury themselves or wedge themselves into tight places. Even though they are sleeping, they are still able to sense danger. Fish sleep for as long as they need, depending on how much energy they have exerted during the day.
Fish also lack eyelashes, as they are unnecessary for survival or comfort.