Omobranchus obliquus, the roundhead blenny or the mangrove blenny, is a species of combtooth blenny found in coral reefs in the Pacific and Indian oceans.Myers, R.F., 1991. Micronesian reef fishes. Second Ed. Coral Graphics, Barrigada, Guam. 298 p. It grows to in length."Roundhead Blenny (Omobranchus obliquus) - Marine Life Identification". www.marinelifeid.com. 2024-08-24. Retrieved 2025-07-21.
Habitat This species can be found in coral reels in both Indian and Pacific oceans, but it is also spotted in areas of Philippines Islands, Guam, New Guinea, Samoa Islands and many more.Revision of the blenniid fish genus Omobranchus with descriptions of three new species and notes on other species of the tribe Omobranchini. (1975). Revision of the Blenniid Fish Genus Omobranchus With Descriptions of Three New Species and Notes on Other Species of the Tribe Omobranchini. https://repository.si.edu/server/api/core/bitstreams/162c61c4-e3f6-46dd-932e-8e88b9168c93/content It is also lives in tidal pools, rocky shores, edges of mangrove swamps, and muddy to sandy bottoms of algae and eel grass.zebra blenny (Omobranchus obliquus) - Species Profile. (n.d.). USGS Nonindigenous Aquatic Species Database. https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=3853 However, it is an invasive species found at Kaneohe, Oahu at places with fouling habitat that are sheltered."Mangrove blennies: Omobranchus rotundiceps". www.hawaii.edu. Retrieved 2025-07-21. Often, this species is spotted deep in salty or seawater, and never seen at depths over ."Resource use and behavioral ecology of the mangrove blenny, Omobranchus rotundiceps obliquus (Garman 1903) - ProQuest". www.proquest.com. Archived from the original on 2024-06-16. Retrieved 2025-07-21.
Behavior Despite this species being found in many different territories, it often prefers living in small groups or in isolation, but they are considered to be juveniles. Like other blenniids, it is a protector and home builder. Due to its rounded head, long body with brown/greenish and yellow hues, it easily blends in with its surroundings. It also has excellent vision due to its bulbous eyes.
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