Pajama Cardinalfish

Max Size: 3.5”
Family: Apogonidae
Care Level: Easy
Lifespan: Up to 5 years
Temperament: Peaceful
Range: Western Pacific
Minimum aquarium size: 20 gallons
Diet: Carnivore
Reef Compatible:  Yes
Color: Green, white, silver
Water Conditions: Normal sea water
Special Requirements: None
Captive Bred Available: Yes
Where To Buy: Fragbox Corals


The Pajama Cardinalfish makes a great choice for Reef Casa tanks over 20 gallons.  They are a colourful, peaceful and completely reef safe fish.  As an added bonus, they are one of the few fish that can be kept in groups in a nano sized aquarium.

Care level

Pajama fish are one of the easiest fish to care for.  They have no special diet or care requirements.  However, because they are a slower moving fish they may be outcompeted for food by faster fish, such as the Sixline Wrasse, so it is important to choose peaceful tankmates.

Size & Sex

These fish grow to a maximum size of about 3.5”.  There are no definitive ways to tell the sexes apart and, unlike many other types of fish, they do not change sex.  Since they are a mouth brooding fish it has been speculated that the males may have a larger mouth, but this has not been proven.


Pajama Cardinalfish are from the Apogonidae family.  This includes all types of Cardinalfish, with their distinctive rayed fins.  This family ranges throughout the world’s oceans and also includes a number of freshwater species.


In the wild, Pajama Cardinalfish are carnivores that prey on small crustaceans that they hunt at night and even in a home aquarium they are one of the few fish that is equally active at night.  In a home tank, they will eat a variety of prepared foods and pellets but also enjoy an occasional feeding of mysis or brine shrimp.

Reef Compatible

Pajama Cardinalfish are 100% reef safe and will not bother any corals or invertebrates.



These fish are among the most peaceful fish available in the saltwater hobby and can be kept singly or in small groups.  They may be bullied by more aggressive tank mates so it is important to select their tank companions carefully.


Water conditions

The Pajama Cardinalfish does not require special water conditions to survive and thrive. Normal salinity of 1.025 is ideal.


With its silver body, green face and fins and distinctive black band and brown spots there is no mistaking a Pajama Cardinalfish.  It has red eyes with very large pupils, an adaptation for hunting at night.  This uniquely coloured fish offers a peaceful way to add a splash of colour to a reef tank.


Because they are a mouth brooding fish there is a much better chance of the fry surviving than with other types of fish.  However, a breeding box or nursery tank is necessary to prevent the fry from being consumed by other tank inhabitants or being sucked into the filtration chamber.