River Goby

Amphidromous. Refers to fishes that regularly migrate between freshwater and the sea (in both directions), but not for the purpose of breeding, as in anadromous and catadromous species. Sub-division of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.Characteristic elements in amphidromy are: reproduction in fresh water, passage to sea by newly hatched larvae, a period of feeding and growing at sea usually a few months long, return to fresh water of well-grown juveniles, a further period of feeding and growing in fresh water, followed by reproduction there (Ref. 82692).

Found in lakes, ponds, rivers and streams. Occurs in brackish water in seasonally intermittent streams.

Awaous tajasica, the sand fish or sandfish, is a species of goby native to fresh and brackish waters of Brazil in South America with reports outside of Brazil considered to be questionable. This species can reach a length of 16.3 cm (6.4 in) SL.