California Horn Shark

The California Horn Shark (Heterodontus francisci) is a hardy, bottom-dwelling temperate species known for its blunt head, small “horns,” and distinctive pattern of saddles and spots. Native to the cool Eastern Pacific, this shark is best kept in a large, well-established aquarium with plenty of open sand for resting and sturdy rock caves for shelter during the day.

Naturally slow-moving and nocturnal, the California Horn Shark spends much of its time resting on the substrate and becoming more active during low-light periods. Tankmates should be peaceful, larger species that will not nip at fins or outcompete the shark for food. Avoid small fish, crustaceans, and other invertebrates that may be viewed as prey.

This species requires cooler water than typical tropical marine fish. A dedicated temperate system with stable, lower temperatures, strong biological filtration, and high oxygen levels is essential. Provide a fine sand substrate to protect the shark’s belly and pectoral fins from abrasion.

Offer a varied, meaty diet including fresh or frozen marine foods such as shrimp, squid, clam, krill, and pieces of fish. Target feeding with tongs helps ensure the shark receives its share while keeping excess waste to a minimum.

• Care Level: Advanced
• Temperament: Generally Peaceful, Predatory
• Minimum Tank Size: 180+ gallons with ample footprint
• Environment: Temperate marine system with cooler water
• Reef Compatibility: Not reef-safe with crustaceans or small fish
• Diet: Carnivore – meaty marine foods, target fed
• Ideal Substrate: Fine sand with solid rock caves for shelter

In the right temperate setup, the California Horn Shark becomes a unique, long-lived centerpiece, rewarding dedicated aquarists with its calm demeanor, interesting appearance, and steady presence on the aquarium floor.