Gasterosteiformes

Gasterosteiformes: Pelvic girdle never attached directly to the cleithra; supramaxillary, orbitosphenoid, and basisphenoid absent; postcleithrum a single bone or absent; branchiostegal rays 1-5; body often with armor of dermal plates; mouth usually small. About 19 species are restricted to freshwater, and another 40 species are found in brackish water (some being variously diadromous or at lest able to commonly enter freshwater and marine water).

• See Fishbase.

Families in this order:

• Aulorhynchidae
• Gasterosteidae
• Hypoptychidae
• Indostomidae
• Pegasidae