Sarcastic fringehead

The sarcastic fringehead, Neoclinus blanchardi, is a small but ferocious fish which has a large mouth and aggressive territorial behavior, for which it has been given its common name. When two fringeheads have a territorial battle, they wrestle by pressing their distended mouths against each other, as if they were kissing. This allows them to determine which is the larger fish, which establishes dominance.