Parrotfish are found in tropical and subtropical oceans throughout the world. They live on coral reefs, rocky coasts and seagrass beds and vary from 30 centimetres long to 50 or so, yet a few – like bumphead parrotfish – grow to over a metre long.
These fish are named for their toothy appearance, which mimics the beak of their feathered namesakes. They have tightly packed teeth that protrude from their jaw bones, which they use to scrape algae from coral and other rocky surfaces. This action plays a significant role in marine bioerosion, referring to natural erosion of by living creatures.
Almost all parrotfish species are hermaphrodites, starting as females (known as the initial phase) and then changing to males (the terminal phase). As always, there are exceptions to this rule – stoplight parrotfish develop directly to males while some female Mediterranean parrotfish never change sex. The juveniles of most parrotfish species are different colour from the adults and some juveniles change colour temporarily to mimic other species.
A number of parrotfish species blow a mucus cocoon from their mouth at night. This protective cocoon encapsulates the fish, presumably to hide its scent from a potential predator but it may also acts as an early warning system should a predators disturbing the membrane.