Smallhead stickleback

The smallhead stickleback (Gasterosteus microcephalus), or resident threespined stickleback, is a fish species, which widespread in the basin of the Pacific Ocean: Japan, also Mexico. Freshwater demersal fish, up to 5.5 cm (2.2 in) length. Habits small streams, where feeds on aquatic insects and other invertebrates.^[1] This taxon is regarded by some authorities as a synonym of the three-spined stickleback (G. aculeatus),^[2] and others treat it as a subspecies of the three-spined stickleback, G. a. microcephalus.^[3]

Smallhead stickleback
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Perciformes
Family:	Gasterosteidae
Genus:	Gasterosteus
Species:	G. microcephalus
Binomial name
Gasterosteus microcephalus Girard, 1854
Synonyms
Gasterosteus aculeatus microcephalus Girard, 1854