Filefish sleep by anchoring itself to SPS with its teeth
Filefish anchoring itself to Acropora with its teeth. And yes, that is a Purple Tang in the background.
Reef fish come up with ingenious methods to safely sleep in the wild: Cirrhilabrus sp. Fairy Wrasses, Parrotfish, et al. form mucus cocoons each night when they tuck themselves into their favorite crevices, masking them from predators and parasites. Macropharyngodon sp. Leopard Wrasses burrow deep into sandy substrates for protection.
We now learn about a Filefish in the Red Sea who sleeps by anchoring itself to branching corals with its teeth!
A team of divers observed an Amanses scopas Filefish chomping down on the tips of Acropora sp. during the middle of the night on two separate occasions. While this species is a known corallivore, the divers concluded the fish was sleeping because it was in a tonic state - unresponsive to light, noise, or even gentle touch. A. scopas' "splotchy" nighttime pigmentation is also different than its daytime appearance (Tang/Surgeonfish owners are familiar with this nighttime pigment shift).
The researchers go on to say: "We suggest that this sleeping behavior may prevent A. scopas from being swept away by strong currents, provide shelter from predators, keep the fish away from contact with the substratum (i.e., avoiding abrasion), and possibly prevent attack by ectoparasites (gnathiid isopods) known to attack fishes while sleeping on the substrate."
Nature finds amazing solutions to life's problems!
(via Coral Reefs)