No, most fish do not blink. Unlike humans and other land animals, fish generally lack eyelids. This is because they don't need eyelids to protect their eyes from drying out; their eyes are constantly bathed in water.
Why Fish Don't Blink
- No Eyelids: The primary reason fish don't blink is the absence of eyelids. As stated in several sources (Natureweb, Eye MD Monterey, Quora), eyelids are a feature that evolved to protect eyes from the air, and fish live in water.
- No Need for Protection from Dryness: Since their eyes are always moist, they don't require eyelids to prevent corneal dryness. (Eye MD Monterey)
- Debris Removal: While they don't blink in the same way humans do, some fish have mechanisms to clear debris from their eyes. A YouTube video shows how some fish use a membrane to clean their eyes. ([YouTube](https://www.youtube.com/watch?v=YOUR_YOUTUBE_LINK_HERE - Note: A valid YouTube link was not provided in the reference; please insert the correct link here)).
Exceptions and Misconceptions
- Eye Movement: The movement of a fish's eyes might be mistaken for blinking. (Reddit - Goldfish, Reddit - Bettafish) Many fish can rotate their eyes.
- Amphibious Fish: A study on an amphibious fish showed that they do have a form of blinking to moisten their eyes, even without tear glands or ducts. (ScienceAlert, Penn State) This is a unique exception.
In summary, while some fish exhibit eye movements that might resemble blinking, and some unique species have evolved alternative methods of eye moisture, most fish species do not blink due to the absence of eyelids and the constant moisture of their aquatic environment.
