The sarcastic fringehead (Neoclinus blanchardi) is a small but hardy saltwater tube-blenny that possesses a large mouth and aggressive territorial behavior, for which it has been given its common name.

[7] The Long-jawed Mudsucker (Gillichthys mirabilis), a similar species, also displays gaping behavior and elongated maxillae, indicating convergent evolution related to shelter defense strategies.

[citation needed][13] When a sarcastic fringehead loses a wrestling match with an intruder, it becomes displaced and must search for a new shelter, a process that can consume significant time and energy that could otherwise be spent foraging or mating.

[15] Their cranial adaptations, especially their enlarged jaws, play a crucial role in territorial displays, which are important for competing for space in their rocky, subtidal habitats.

[7] Divers have observed that despite the fish’s small size, typically between 6 and 10 inches, its territorial aggression and jaw-flaring display can be deceptively intense during encounters.

[7] The evolution of the Sarcastic Fringehead’s aggressive display is a prime example of heterochrony, where changes in the timing and rate of development have resulted in enhanced features that amplify its territorial and mating behaviors.

[7] Due to the size of their mouths, sarcastic fringeheads are categorized as ram-suction feeders, relying on fast burst speeds and moderate suction to capture prey.

[18] Variability in daily foraging time, influenced by the frequency of territorial encounters, may shape evolutionary adaptations in fringeheads, including gut size and efficiency based on food availability.

[20] The sarcastic fringehead is classified as 'Least Concern' by the IUCN due to relatively low threats from human activities and its occurrence in areas that are protected.

When caught accidentally, sport and commercial anglers often find it challenging to handle due to the likelihood of being bitten by its needle-like teeth if it becomes agitated.