Taxonomy
Rarity
Abundance rates how many are in suitable habitat. Find difficulty rates how hard it is to locate one on a daylight snorkel or freedive through 50 ft. A higher find score means a harder search. The rarity category also reflects the kind of encounter; it is not an average of the 2 scores.
Seasonality
Location
The plain cardinalfish ranges from San Clemente Island in Southern California to the Gulf of California and the offshore islands of the eastern Pacific. It lives on rocky reefs at about 30 to 100 feet and stays inside shelter by day. The published limit names an island, so mainland photos at La Jolla sit at the edge of what is documented.
Deep Dive
This is a small, plain fish, as the name promises. It reaches about 3.5 inches, with a compressed oblong body, a large head, big eyes and a large slanted mouth. It is reddish pink all over with no markings, and tends to be darker with a bluish tinge toward the front.
Cardinalfish hide by day and hunt at night, when this species leaves shelter and forms small schools. It eats small fish, crustaceans including crabs and shrimp, mollusks such as snails and other small animals without backbones.
Its breeding is the unusual part. The male holds the fertilized eggs in his mouth for several days, then releases hundreds of tiny larvae into the ocean, where they drift for several weeks before settling as juveniles. Mexican Fish says the species is poorly studied.
Where to Find Them
Researched habitat and range candidates
San Diego · 9 beaches
These locations have suitable habitat within the species range. An assignment is a possible encounter, not a confirmed sighting at every beach. Season, depth, and local conditions still matter. Historical habitat without present-day evidence is excluded.