A species flock may also arise when a species acquires an adaptation that allows it to exploit a new ecological niche. For example, the Antarctic icefishes are a species flock of 122 marine fishes that have an adaptation that allows them to survive in the freezing, ice-laden waters of the Southern Ocean because of the presence of an antifreeze glycoprotein in their blood and body fluids.
The cichlids are a group of perciform fishes that contains a number of species flocks found in the lakes and rivers of central and southern Africa.