California halibut

Paralichthys californicus

The California halibut is a large flatfish of the eastern Pacific, ranging from Washington south to Baja California and occasionally into the Gulf of California. Unusually among flatfish it shows no fixed eye-side dominance: during metamorphosis, roughly six weeks after hatching, one eye migrates over the head, and about equal numbers of fish end up looking left or right. Adults are grey-brown flecked with darker spots and can shift tone and pattern within seconds to match mud, gravel, or sand, becoming nearly invisible until they move. Females grow faster and reach larger sizes than males; most individuals run 30 to 60 cm, though rare giants exceed 1.5 m and 30 kg. It is told apart from the much larger, cold-water Pacific halibut by its warmer range, smaller size, and strongly arched lateral line. A camouflaged ambush hunter, it lies half-buried in sediment and lunges upward to seize anchovies, market squid, and other small fish and invertebrates. Spawning runs from spring into summer in offshore water, and shallow estuaries such as San Francisco Bay act as vital nurseries for the young. Divers most often meet it resting motionless on open sand near coastal reefs and eelgrass flats, where a patient, slow approach can get quite close before the fish erupts away in a puff of silt.