HomeFish encyclopediaRay-finned fishesPerch-like fishGobiesLongjaw mudsucker Longjaw mudsucker (Gillichthys mirabilis) Scientific name: Gillichthys mirabilis Cooper, 1864 The Longjaw mudsucker (Gillichthys mirabilis) is a brackish-water fish of the family Gobiidae. Native range: Eastern Pacific, Tomales Bay in northern California, USA to Gulf of California. BiologyInhabits tidal flats, bays and coastal sloughs. Prefers mud bottom in shallow water. Non-emerging air-breather. Oviparous. Males guard the eggs which are found attached to the walls of brood chamber.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameGillichthys mirabilisFamilyGobiidae (Gobies)OrderPerciformes (Perch-like fish)ClassActinopterygii (Ray-finned fishes)Maximum length21.0Common length13.0EnvironmentMarine; brackish; demersalClimateSubtropicalDistributionEastern Pacific: Tomales Bay in northern California, USA to Gulf of California.Conservation status (IUCN)Least Concern (LC)Threat to humansHarmlessUsesBait: usuallyResilienceHigh, minimum population doubling time less than 15 months (tmax=2;) SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026