Australian researchers on Wednesday found that fish have developed their own mosquito nets in order to get a good night's sleep.
Scientists from the University of Queensland have conducted ground breaking experimental studies on the mucous-like cocoons.
According to Researcher Dr. Alexandra Grutter, while most fish guide books and biology textbooks presumed the cocoons protected fish from nocturnal predators such as moray eels, no experimental studies had examined their function.
The study has found the cocoons protect fish from the parasites, ectoparasitic gnathiids, that bite like mosquitoes.
Dr. Grutter said when cleaner fish sleep at night, mucous cocoons act like mosquito nets, allowing fish to sleep safely without being constantly bitten.
"In our study, we exposed coral reef parrotfish with and without cocoons to ectoparasitic gnathiids overnight," Dr. Grutter said in a statement released on Wednesday.
"Fish without mucous cocoons were attacked more by gnathiids than the fish with cocoons.
"Fish that spent their time building the cocoons before tucking in to bed at night were protected, much like humans putting on a mosquito net."
The research is published in Biology Letters on Wednesday.