Gobies are extremely successful in their ability to exploit microhabitats inaccessible to most other fishes; they are found from subarctic streams in Siberia to mountain streams at altitudes of 2,000 m on islands to ocean depths of 800 m. On coral reefs, they can be found in the numerous cracks and crevices or out in the open among corals (Gobiosoma). Others build burrows (Signigobius) or use the burrows of invertebrates, ranging from polychaete worms to clams. Members of the genera Boleophthalmus, Periophthalmus, Periophthalmadon, Scartelaos, and Bathygobius have uniquely adapted to tidepools, mudflats and mangrove swamps, where some even climb out of the water for extended periods to forage (discussed further in Food Habits). Still others build numerous holes along sandy beaches (Coryphopterus) or compose a large part of the fishes in estuaries, inland seas and continental shelf environments as deep as 800 m.
The approximately 200 species found in freshwater form a separate category of gobies. Gobies are extremely successful in freshwater habitats where few other fish are found, such as oceanic islands. Half of the freshwater species are part of the subfamily Sicydiinae. Members of this group exhibit a high degree of island endemism and some even reach the headwaters of high-elevation rivers (2,000 m) in mountains. Some species have a short marine life-stage while others have evolved to live completely within freshwater environments.
Habitat Regions: temperate ; tropical ; saltwater or marine ; freshwater
Aquatic Biomes: pelagic ; benthic ; reef ; lakes and ponds; rivers and streams; temporary pools; coastal ; abyssal ; brackish water
Other Habitat Features: estuarine ; intertidal or littoral