Invasion History

First Non-native North American Tidal Record: 1985
First Non-native West Coast Tidal Record: 1985
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Tridentiger bifasciatus (Shimofuri Goby) is native to Asia. It is found in fresh and brackish waters from Hokkaido and northern China to Taiwan and Hong Kong (Matern et al. 1995; Froese and Pauly 2009; Yagi et al. 2011). We have treated it as continental or freshwater species since it has not been reported at salinities above 22 ppt in the field, and does not tolerate salinities above 17 PSU in the laboratory (Matern et al. 1995; Matern 2001). This level of salinity tolerance is comparable to that of many freshwater fishes (Schwartz 1965).

North American Invasion History:

Invasion History on the West Coast:

Tridentiger bifasciatus has only been found outside its native range in California. Initially, it was confused with the marine species T. trigonocephalus, with which it had been lumped by taxonomists. However, when T. bifasciatus was reinstated as a separate species, Matern et al. (1995) reexamined Tridentiger species from fresh and brackish parts of the Sacamento-San Joaquin Delta and found T. bifasciatus (Matern et al. 1995). This goby was first collected in the Delta in 1985. By 1989 it had become the most abundant fish species in Suisun Marsh (Matern et al. 1995). In 1987, a specimen was collected at the John Skinner Delta Fish Protective Facility near Byron, Contra Costa County, on the San Joaquin River. This is the intake for the California Aqueduct, which supplies water to Los Angeles. In 1990, T. bifasciatus was collected in Pyramid Reservoir, at the far end of the aqueduct, 513 km to the south of the Skinner facility. In 1992, some fish were collected below the Pyramid Reservoir, but they had not spread into the Santa Clara or Santa Ynez rivers, which reach the coast (Matern et al. 1995). By 2016, Shimofuri Gobies had been collected in seven southern California reservoirs, from Pyramid Reservoir, east of Oxnard, to Otay Reservoir, east of San Diego. They were collected below dams in the Santa Clara River system, but as of 2015, they have not been found in Santa Clara estuary, where they pose a threat to the endangered Tidewater Goby (Eucyclogobius newberryi) (Howard and Booth 2016).

Invasion History Elsewhere in the World:

In November 2022, 2 specimens of Tridentiger biasciatus were caught in the Gent–Terneuzen canal, Belgium, )at a salinity of 7-8 PSU,  These are the first recorded specimens of this fish in Europe. (Verhelst and Verreycken 2023).  


Tridentiger bifasciatus (Shimofuri Goby) is a freshwater and estuarine fish. It is morphologically very similar to T. trigonocephalus, with which it was formerly considered conspecific. Ecologically, the biggest difference between the species is that T. bifasciatus is unable to tolerate marine salinities above 17 PSU, while T. trigonocephalus has not been reported from fresh water (Matern and Fleming 1995; Matern 2001).

Tridentiger bifasciatus has the typical features of the family Gobiidae, including the two pelvic fins united to form a conical sucking disk, a spiny anterior and a soft posterior dorsal fin, and eyes near the top of the head. The dorsal fins have 6-7 spines and 11-14 rays, respectively, that are separated by a gap. The uppermost ray of each pectoral fin is attached and smooth (Matern and Fleming 1995). The lateral line is not noticeable. This goby is relatively fat, with a wide flat head. There are small sensory canal pores on the top of the head in the interorbital region (Matern and Fleming 1995). Colors are highly variable, but often dark or light brown, with a row of dark-brown mid-lateral spots. There are small white speckles on the head that extend to the ventral surface. The dorsal and anal fins are edged with orange (Matern and Fleming 1995). This fish reaches a maximum length of 110 mm (Froese and Pauly 2018).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Chordata
Subphylum:   Vertebrata
Superclass:   Osteichthyes
Class:   Actinopterygii
Subclass:   Neopterygii
Infraclass:   Teleostei
Superorder:   Acanthopterygii
Order:   Perciformes
Suborder:   Gobioidei
Family:   Gobiidae
Genus:   Tridentiger
Species:   bifasciatus


Tridentiger bifasciatus (Akihito & Sakamoto, 1989)

Potentially Misidentified Species

Tridentiger barbatus
Can be confused as larvae or early juveniles.

Tridentiger trigonocephalus
Long considered conspecific, but morphologically different, and stenohaline-marine (Matern et al. 1995)



Tridentiger bifasciatus ranges from cold-temperate to warm-temperate climates in fresh and brackish waters (Matern et al. 1995; Froese and Pauly 2018). It tolerates gradual temperature increases up to 37 C and gradual salinity increases up to 17 PSU, making dispersal through marine waters unlikely (Matern 2001). It is most abundant in freshwater and low-salinity habitats (Matern and Fleming 1995). Habitats include marshes, freshwater reservoirs, and probably natural and artificial structures that provide shelter (Matern and Fleming 1995). The Shimofuri Goby is a generalist predator. Prey in Suisun Marsh, in the San Francisco estuary, is amphipods and copepods, but it also preys on introduced hydroid Cordylophora caspia, and the cirri of the introduced barnacle Amphibalanus improvisus (Matern et al. 2005). In the laboratory it is aggressive towards the endangered Tidewater Goby, Eucyclogobius newberryi (Matern 2010).


Amphipods, Polychaetes, Oligochaetes; Hydroids

Trophic Status:




General HabitatFresh (nontidal) MarshNone
General HabitatGrass BedNone
General HabitatNontidal FreshwaterNone
General HabitatTidal Fresh MarshNone
General HabitatSalt-brackish marshNone
General HabitatUnstructured BottomNone
General HabitatCanalsNone
Salinity RangeLimnetic0-0.5 PSU
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Tidal RangeSubtidalNone
Vertical HabitatNektonicNone
Vertical HabitatEpibenthicNone

Life History

Tridentiger bifasciatus (Shimofuri Goby) is a freshwater and estuarine fish. In the laboratory, males are territorial and guard nests in plastic tubes, attracting females (Matern and Fleming 1995). They nest in freshwater or brackish-water clam shells (Corbula; , Corbicula) as well as cans, bottles, and other trash. Eggs hatch in 9 days, at 20 C, and are guarded by the male (Matern and Fleming 1995). Females in an introduced freshwater population has 2300 to 18,000, with a mean of 8,200 eggs (Qin et al. 2020).Larvae are planktonic and probably use vertical migration for retention in the estuary (Bennett et al. 2001). Comparisons between a Chinese freshwater introduced population and the San Francisco estuary population suggest that this species has great plasticity in its life history (Qin et al. 2020).

Tolerances and Life History Parameters

Maximum Temperature (ºC)37Temperature was increased by 0.1 C per minute (Critical Temperature Maximum; The endpoint was loss of equilibrium) (Matern 2001).
Minimum Salinity (‰)0This is a freshwater species.
Maximum Salinity (‰)17Salinity was increased by 1 ppt per 12h; the endpoint was loss of equilibrium (Matern 2001). This level of salinity tolerance is typical for a stenohaline freshwater fish.
Minimum Reproductive Salinity0Field and lab Matern et al. 1995
Maximum Reproductive Salinity5Lab, Matern et al. 1995
Maximum Length (mm)110Froese and Pauly 2014
Broad Temperature RangeNoneCold temperate-Subtropical
Broad Salinity RangeNoneNontidal Limnetic-Mesohaline

General Impacts

Tridentiger bifasciatus (Shimofuri Goby) is a rapidly spreading invader in fresh and estuarine waters in California. It is regarded as a potential competitor with the endangered native Tidewater Goby (Eucylogobius newberryi) (Matern and Fleming 1995; Matern 2001). It is probably an important prey item for native and introduced predatory fishes.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
P090 San Francisco Bay 1985 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Precht, William F. Hickerson, Emma L.; Schmah, George P.; Aronson, Richard B. (2014) The invasive coral Tubastraea coccinea (Lesson, 1829): Implications for natural habitats in the Gulf of Mexico and the Florida Keys, Gulf of Mexico Science 2014: 55-59

Bennett, William A.; Kimmerer, Wim J.; Burau, Jon R. (2002) Plasticity in vertical migration by native and exotic estuarine fishes in a dynamic low-salinity zone., Limnology and Oceanography 47(5): 1496-1507

Bogantes, Viktoria E.; Boyle, Michael J.; Halanych, Kenneth M. (2021) New reports on Pseudopolydora (Annelida: Spionidae) from the East Coast of Florida, including the non-native species P. paucibranchiata, BioInvasions Records 10: 577-588

Feyrer, Frederick (2004) Ecological segregation of native and alien larval fish assemblages in the southern Sacramento-San Joaquin Delta., American Fisheries Society Symposium 39: 67-79

Feyrer, Frederick; Herbold, Bruce; Matern, Scott A.; Moyle, Peter (2003) Dietary shifts in a stressed fish assemblage: consequences of a bivalve invasion in the San Francisco estuary., Environmental Biology of Fishes 67: 277-288

Froese, R.; Pauly, D. (Editors). 2002-2024 FishBase.(World Wide Web electronic publication).. <missing URL>

Grabowski, Michal; Bacela, Karolina; Konopacka, Alicja;Jazdzewski, Krzysztof (2009) Salinity-related distribution of alien amphipods in rivers provides refugia for native species, Biological Invasions 11: 2107-2117

Kajihara, Hiroshi; Sun, Shi-Chun; , Chernyshev, Alexei V.; Chen, Hai-Xia; Ito, Katsutoshi; Asakawa, Manabu; Maslakova, Svetlana A.;Norenburg; Jon L. Strand, Malin; Sundberg, Per: Iwata, Fumio (2013) Taxonomic Identity of a Tetrodotoxin-Accumulating Ribbon-worm Cephalothrix simula (Nemertea: Palaeonemertea): A Species Artificially Introduced from the Pacific to Europe, Zoological Science 30(11): 985-997

Liu, Wenliang; Liang, Xiaoli ; Zhu, Xiaojing (2015) A new record and mitochondrial identification of Synidotea laticauda Benedict, 1897 (Crustacea: Isopoda: Valvifera: Idoteidae) from the Yangtze Estuary, China, Zootaxa 4294: 371-380

Massé, Cécile; Jourde, Jérôme; Fichet, Denis; Sauriau, Pierre-Guy; Dartois, Manon; Ghillebaert, François; Dancie, Chloé (2022) Northern range expansion of the Asian mussel Arcuatula senhousia (Benson, 1842) along the French Atlantic coasts, BioInvasions Records 11: Published online

Matern, Scott A. (2001) Using temperature and salinity tolerances to predict the success of the shimofuri goby., Transactions of the American Fisheries Society 130: 592-599

Matern, Scott A.; Brown, Larry R. (2005) Invaders eating invaders: exploitation of novel alien prey by the alien shimofuri goby in the San Francisco estuary, California., Biological Invasions 7: 497-507

Matern, Scott A.; Fleming, Kevin J. (1995) Invasion of a third Asian goby, Tridentiger bifasciatus, into California., California Fish and Game 81(2): 71-76

Matern, Scott; Meng, Lesa; Pierce, Leslie C. (2001) Native and introduced larval fishes of Suisun Marsh, California: the effects of freshwater flow., Transactions of the American Fisheries Society 130: 750-765

Moyle, Peter B. (2000) A list of freshwater, anadromous, and euryhaline fishes of California., California Fish and Game 86(4): 244-258

Schwartz, Frank J. (1965) Natural salinity tolerances of some freshwater fishes, Underwater Naturalist 2(2): 13-15

Verhelst, Pieterjan; Verreycken, Hugo (2023) First record in Europe of the Asian gobiid, shimofuri (marbled) goby Tridentiger bifasciatus Steindachner, 1881, Journal of Fish Biology Published online: <missing location>
DOI: 10.1111/jfb.15362