Smooth Hound Shark

The Smooth Hound Shark, Mustelus californicus, is a sleek, highly active shark with a streamlined gray to gray-brown upper body fading into a pale or white underside. Its elongated snout, graceful swimming style, and classic shark profile make it an impressive centerpiece for exceptionally large marine displays. Unlike bottom-resting bamboo and epaulette sharks, the Smooth Hound spends a significant amount of time actively cruising near the substrate and through open water.

Native to the eastern Pacific from California into Mexican waters and the Gulf of California, this species inhabits coastal continental shelves, shallow bays, and sandy or muddy environments. Its flattened, pavement-like teeth are adapted primarily for crushing crustaceans and other benthic prey rather than capturing large fish.

The Smooth Hound Shark is a specialized saltwater fish suitable only for advanced aquarists with extremely large, purpose-built systems. Its adult size, continuous swimming behavior, cool-water requirements, high oxygen demand, and need for an expansive footprint make it far more appropriate for large shark ponds and public-aquarium-style installations than conventional home reef aquariums.

Quick Care Guide

Care Level: Expert Only
Minimum Tank Size: 3,000 gallons
Temperament: Predatory
Diet: Carnivore
Reef Safe: No
Region: Eastern Pacific – California to Mexico and the Gulf of California
Scientific Name: Mustelus californicus

Tank Requirements

The Smooth Hound Shark requires an exceptionally large aquarium or indoor marine pond designed around continuous swimming. Footprint is just as important as total water volume. Wide oval, rounded, or racetrack-style systems are preferable because they allow the shark to maintain a natural swimming pattern without repeatedly encountering tight corners.

Provide extensive unobstructed swimming space with a broad area of fine sand. Avoid coarse gravel, sharp rock, rough artificial decorations, and abrasive surfaces that can damage the shark's underside or fins. Any rockwork should be minimal, extremely stable, and positioned so it does not restrict swimming lanes.

This is a temperate to subtropical species and should not be treated as a typical 78°F tropical reef shark. Chilling equipment may be necessary depending on ambient conditions. Excellent gas exchange, vigorous aeration, powerful biological filtration, protein skimming, and high dissolved oxygen are essential.

A secure cover or sufficiently high pond perimeter is important because smoothhounds are active swimmers and can jump from open systems when startled.

Long-term housing must be planned before acquisition. A juvenile may appear relatively small, but adults develop into large, constantly moving sharks requiring public-aquarium-scale swimming space.

Diet and Feeding

The Smooth Hound Shark is a carnivore specialized primarily for feeding on bottom-dwelling crustaceans and other marine invertebrates. Its blunt crushing teeth are particularly well suited to crabs, shrimp, mollusks, and similar prey.

Offer a varied marine diet including shrimp, squid, clam, mussel, scallop, crab, and appropriately sized pieces of marine fish. Smaller individuals can also receive krill and other suitably sized marine crustaceans.

Foods should be fresh or properly frozen and varied rather than relying on one seafood item exclusively. Supplementation with an appropriate marine vitamin preparation can help prevent nutritional deficiencies when feeding prepared seafood diets long-term.

Juveniles generally benefit from smaller, more frequent meals, while established adults can receive appropriately portioned meals several times per week according to body condition. Avoid chronic overfeeding, which can negatively affect the shark while placing an unnecessary burden on water quality.

Routine use of freshwater feeder fish is unnecessary and should be avoided.

Temperament and Tankmates

The Smooth Hound Shark is an active predator but is not generally known for the highly aggressive behavior associated with many larger predatory sharks. Its natural diet focuses heavily on crustaceans and other benthic animals, although small fish may also be eaten.

Tankmates must be selected carefully. Small fish, shrimp, crabs, and other animals that can be captured or swallowed should be considered potential prey. Suitable companions must be large enough to avoid predation while also being peaceful enough not to harass the shark.

Avoid aggressive triggerfish, puffers, large angelfish, or other species that may nip at the shark's eyes, fins, or body. Slow-moving sharks can suffer serious injuries from persistent fin-nipping tankmates.

Housing multiple sharks requires substantially more swimming area than a single specimen and should only be attempted in systems specifically engineered for large elasmobranchs.

Reef Compatibility

The Smooth Hound Shark is not considered reef safe for a conventional reef aquarium. Although it is not primarily a coral-eating species, ornamental shrimp, crabs, mollusks, and small fish may be consumed.

Its large adult size and active swimming behavior also make delicate coral aquascapes impractical. Rockwork and corals can obstruct necessary swimming space or cause injuries if the shark collides with them.

The species' preference for cooler, highly oxygenated water can also conflict with the requirements of many tropical reef organisms. A spacious shark-specific fish-only system with a large sandy bottom is the more appropriate long-term environment.

Water Parameters

Temperature: 60–72°F
Specific Gravity: 1.023–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Excellent dissolved oxygen and temperature stability are especially important. Avoid allowing the aquarium to remain at typical warm tropical reef temperatures for extended periods, particularly when oxygen availability is limited.

Common Considerations

• Extremely large system required: Adult Smooth Hound Sharks require thousands of gallons and an expansive swimming footprint rather than simply a deep aquarium.

• Temperate species: This is not a typical tropical shark, and a properly sized chiller may be required to maintain appropriate long-term temperatures.

• High oxygen demand: Powerful circulation, aeration, and gas exchange are essential, particularly as water temperature increases.

• Soft substrate required: Fine sand and smooth surfaces help protect the underside, mouth, and fins from abrasions that can lead to secondary infections.

• Active swimming behavior: Rounded or very wide aquarium designs with long uninterrupted swimming paths are strongly preferred over conventional narrow rectangular tanks.