Cabrillo Marine Aquarium

California Grunion

Leuresthes tenuis


Fun Facts

    Unlike other fish, grunion come completely out of the water to lay their eggs in the sand.

    Female grunion lay about 300 to 3,000 eggs and may spawn 4 to 8 times per season.



  California grunion are small silvery fish found on the coast of southern California and northern Baja California. They have bluish-green backs with the rest of the body a shiny-silver color. Their average length is between 5 and 6 inches. This fish belongs to the family Atherinidae, commonly known as silversides. Other common atherinids found in California are the jacksmelt, Atherinopsis californiensis and the topsmelt, Atherinops affinis.
Along southern California's sandy beaches, from March through September, one of the most remarkable life cycles in the ocean is completed; the California grunion comes ashore to spawn. The curious fact is that 1 to 3 hours after the high tide, female grunion and their male suitors wash up on the shore en masse. The females wriggle tail first into the sand laying some 300 to 3,000 eggs while the males encircle them depositing milt along her body fertilizing the eggs below the sand surface. In this protected pod, the eggs develop for some 10 days until the next high tide agitates and triggers the baby grunion to hatch. They will mature in approximately one year and will complete the cycle. Grunion live for 3 to 4 years and females may spawn 4 to 8 times per season. Grunion may be eaten by many kinds of fish including California halibut and croakers; and probing shorebirds, sand worms, beetles and beach hoppers eat their eggs.
Come to the Aquarium and watch the grunion on the beach during our Meet the Grunion program!
To learn more about the California grunion, check out the Grunion: Fact or Fiction? exhibit in the Sandy Beach Room. Also, when present, California grunion can be found in the Aquarium in tank number 34 or in the Aquatic Nursery.