Petroscirtes variabilis
(sabretoothed blenny)
Marine Fishes
Exotic |
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Common name: sabretoothed blenny
Synonyms and Other Names: variable saber-toothed blenny
Taxonomy: available through
www.itis.gov
Identification: Petroscirtes variabilis are elongate and laterally compressed with a single dorsal fin (Allen and Erdmann 2012). This species is variable in color and densely mottled with white and dark olive spots. Ferraris and Murdy (1983) suggest this species is sexually dichromatic with females more green dorsally and lighter brown below and males more orange-brown dorsally. There is a short flap on the posterior of the nostril and unbranched cirrus on the chin (Randall et al. 1990). The fins are yellowish with the dorsal and anal fins having dark spots (Randall et al 1990). Members of this tribe of blennies, Nemophini, possess large curved canine teeth on the front of the lower jaw (Allen and Erdmann 2012).
Size: This species can attain a maximum size of 7.5 cm total length (Allen and Erdmann 2012).
Native Range: Petroscirtes variabilis is native to the eastern Indian and western Pacific Oceans from Sri Lanka to Papua New Guinea and eastern Australia, north to Taiwan throughout most of the East Indian region (Allen and Erdmann 2012).
Nonindigenous Occurrences:
An individual was photographed in Kawaihae Harbor, Hawaii in April 2025 (On 2025).
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Petroscirtes variabilis are found here.
Table last updated 3/9/2026
† Populations may not be currently present.
Ecology: Petroscirtes variabilis inhabits sea grass beds and weedy sections of coastal reefs up to 5 meters deep (Allen and Erdmann 2012). This species is omnivorous, feeding primarily on epiphytes that grow on sea grass (Gilby et al. 2016) and crustaceans as well potentially practicing lepidophagy, the eating of fish scales (Ferraris and Murdy 1983). Ferraris and Murdy (1983) observed P. variabilis hovering motionless in a vertical head-up orientation amongst sea grass. They hypothesized that the coloration of the fish and vertical orientation behavior would allow the fish to approach potential prey undetected for lepidophagy. The large canines appear to be more for defense and intraspecific fighting rather than feeding (Allen and Erdmann 2012, Ferraris and Murdy 1983). Petroscirtes variabilis lays demersal eggs guarded and tended by the male parent (Allen and Erdmann 2012, Randall et al. 1990). Several females may lay eggs in the nest (Shibata and Kohda 2007). Eggs are laid in abandoned worm tubes, dead coral crevices, and even empty bottles and cans (Allen and Erdmann 2012). Prakash and Kumar (2025) observed several P. variabilis in empty Pinna clam shells with eggs in at least one of the shells.
Means of Introduction: Unknown. This species could be a potential marine debris hitchhiker as it was observed on marine debris east of the Hawaiian Islands where they had not been previously reported (Benadon et al. 2023).
Status: Unknown
Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.
References: (click for full references)
Allen, G.R., and M.V. Erdmann. 2012. Reef Fishes of the East Indies, Volume II, Tropical Reef Research, Perth, Australia.
Benadon, C., C.J. Zabin, L. Haram, J.T. Carlton, N. Maximenko, P. Nelson, M. Crowley, and G.M. Ruiz. 2023. Marine debris facilitates the long-distance dispersal of fish species. Marine Biology 171:43 https://doi.org/10.1007/s00227-023-04365-3
Ferraris, C.J. Jr., and E.O. Murdy. 1981. Aspects of sexual dimorphism and feeding in Petroscirtes variabilis Cantor (Osteichthys: Blenniidae). Micronesia 17(1-2):157-160.
Gilby, B.L., C.J. Henderson, I.R. Tibbetts, and D.D. Burfeind. 2016. Quantifying the influence of small omnivorous fishes on seagrass epiphyte load. Journal of Fish Biology 89(3):1905-1912.
On, H.V. 2025. iNaturalist observation: https://www.inaturalist.org/observations/276442797 (accessed 28 August 2025)
Prakash, S., and A. Kumar. 2025. Life in the dead shell: utilization of dead Pinna shells by the blenny fish Petroscirtes variabilis Cantor, 1849 (Blennidae). The Science of Nature 112:9 https://doi.org/10.1007/s00114-025-01960-w
Randall, J.E., G.R. Allen, and R.C. Steene. 1990. Fishes of the Great Barrier Reef and Coral Sea. University of Hawaii Press, Honolulu, Hawaii.
Shibata, J., and M. Kohda. 2007. Diel patterns in reproductive events of the blenniid fish Petroscirtes breviceps in the temperate waters of southern Japan. Ichthyological Research 54:412-415.
Author:
Brown, M.E.
Revision Date: 2/25/2026
Citation Information:
Brown, M.E., 2026, Petroscirtes variabilis Cantor, 1849: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=3985, Revision Date: 2/25/2026, Access Date: 3/9/2026
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.
