Pajama Cardinal Care Guide

The Pajama Cardinal, also known as the Spotted Cardinal or Pajama Cardinalfish, is a mid-tank schooling fish. You can go with a pair, but Pajama Cardinals will be happier in a group of at least 6.

These fish are ideal for both small and large aquarium communities and are peaceful creatures that will not bully others in the tank. However, you do need to be mindful of the other fish in the tank. Pajama Cardinals absolutely can not be kept with larger predatory fish, as the aggressive fish will view your Pajama Cardinal as a snack; you could lose the entire shoal.

If you are considering staggering active times when curating your tank, you should know that Pajama Cardinals are nocturnal, and will be much more active at night.

Another great feature is that Pajama Cardinals are reef compatible. When you are planning a saltwater tank, it’s good to know which species to avoid if you are housing fish that require reefs in order to thrive.

Pajama Cardinals, the scientific name Sphaeramia nematoptera, are native to the Western Pacific Ocean. Not listed as an endangered or vulnerable species, Pajama Cardinals can be found happily swimming all the way from Fiji to Java. Marlin and Dory definitely ran into these guys as they crossed the Great Barrier Reef.

n the wild, the group around the rocky areas of lagoons to rest and hide; at night, they become more active and search for food, preferring small crustaceans. They are carnivores and exist on live food in their natural habitat.

They swim in shallow waters in the ocean, from 3 to 50 feet, so they won’t be bothered by the smaller depth of the home aquarium.

~Typical Behavior~

These fish are really fun to watch because instead of a wiggly swimming style, Pajama Cardinals float with still bodies, darting from place to place.

Pajama Cardinals are peaceful creatures with others as well as their own kind. However, the males do get somewhat aggressive when they are breeding. By that I mean they are hostile, but not violent.

They do have hierarchical social structures, similar to other schooling fish. Even though they are nocturnal, they are not able to fully hide, and you will see them swimming during the day; they’re just more active at night.

Pajama Cardinals do mark their territory and will find an area of the tank to claim as their home. Even when they go out for food or exploring, they return to their home spot. If there is a rock or coral pattern that has an overhang, you can bet they will choose that spot for their home base.