Smallhead stickleback
The smallhead stickleback (Gasterosteus microcephalus) is a stickleback. Some authorities think it is a synonym of Gasterosteus aculeatus or a subspecies of that taxon.
References
- Froese, Rainer; Pauly, Daniel (eds.) (2022). "Gasterosteus microcephalus" in FishBase. August 2022 version.