Fish
Cardinalfish
Apogonidae · also called cardinalfishes
Holding a mouthful of developing eggs with careful precision, a male cardinalfish waits out the night in the shelter of the reef, one of several hundred species within a family known both for this unusual parental care and for the large, light-gathering eyes that suit its mostly nocturnal lifestyle.
Overview
The cardinalfish, family Apogonidae, is native to ocean and coastal reef habitat across tropical and subtropical regions worldwide. Its large, diverse species count, widespread mouthbrooding parental care, and mostly nocturnal lifestyle make it one of the most ecologically interesting and commonly encountered reef fish families found anywhere.
Fatherhood carried in the mouth
Across much of the cardinalfish family, the responsibility of protecting the next generation falls to the male, who carries a mouthful of fertilised eggs for days at a time, forgoing normal feeding until the eggs are ready to hatch.
Status
Least Concern as a family, remaining widespread and generally common across suitable reef habitat worldwide, though individual species vary.
Cardinalfish: common questions
Is the cardinalfish the same thing as a Banggai cardinalfish?
No, the Banggai cardinalfish is one specific, well-known species within the much larger cardinalfish family, which includes several hundred species found across tropical and subtropical reefs worldwide.
Why do male cardinalfish carry eggs in their mouths?
Many cardinalfish species are mouthbrooders, with the male holding a mouthful of fertilised eggs until they hatch, a strategy that protects the developing eggs from predators.
Are cardinalfish active during the day or at night?
Most cardinalfish species are active mainly at night, aided by unusually large eyes suited to low-light conditions, and tend to shelter near reef structure during the day.
Where are cardinalfish found?
They are native to ocean and coastal reef habitat across tropical and subtropical regions worldwide.