* They are diurnal: Demoiselle fish are active during the day and primarily rest at night.
* They are reef dwellers: They are found in shallow, tropical reefs and often hide in crevices and coral during the night.
* Sea caves are not their preferred habitat: While they may occasionally venture into caves for shelter, they don't use them for sleeping.
Why do they hide during the night?
* Predator avoidance: They are small and vulnerable at night, so they hide to avoid predators.
* Energy conservation: They reduce their energy expenditure by minimizing activity at night.
While they don't sleep in sea caves, they do have interesting sleep habits:
* They rest with their eyes open: unlike mammals, their eyes don't close when they rest.
* They are able to sleep while swimming: they can remain still or swim slowly while resting.
Let me know if you have any other questions!