California Grunion Identification Guide

Key identification features

• Slender, elongated body typically 5-7 inches (12-18 cm), larger than most silversides
• Blue-green to olive back fading to a bright silvery stripe along the sides and a pale belly
• Small, slightly pointed head with a small mouth and no barbels
• Two separated dorsal fins and a moderately forked tail
• Relatively large, easily visible scales compared to smaller silverside relatives
• Body remains fully silvery and streamlined even in large adult schools, with no bold spotting or barring

Common look-alikes

• Atlantic Silverside: similar shape but found only on the Atlantic coast, never the Pacific
• Inland Silverside: smaller and found in brackish or fresh inland water rather than open Pacific surf
• Topsmelt: has a more compressed body and a greenish rather than sharply silvery stripe

Where you'll see one

Found along sandy beaches and nearshore waters of Southern California and Baja California, best known for coming ashore at night on spring high tides to spawn directly in the wet sand. Outside spawning runs it schools just offshore in the surf zone.