More info from Discovery.com:
This small, scrappy fish found along the Pacific Coast from San Francisco to Baja California, Mexico, maintains a relatively small zone of personal space around its home, usually a shell, a can or a bottle. When an intruder invades that space, the fringehead attacks fearlessly and aggressively, baring its teeth and snapping its jaws…
Why invest so much time and energy into keeping away unwanted solicitations? Because in the fringehead’s preferred habitat — on sandy or muddy ocean bottoms just beyond the breaker zone — competition for resources is fierce. To ensure they get their fair share of food and space, fringeheads stake out a territory that they can realistically defend… Some scientists estimate they consume almost 14 times their body weight per year.
Watch this next: The Mudskipper, an amazing amphibious fish.