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Info  Quick Care, Species Info, Aquarium Care & Photos
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Pajama Cardinalfish
(Sphaeramia nematoptera)
Quick Care FactsCare Level: Easy
Temperament: Peaceful
Maximum Size: 3"
Minimum Tank Size: 30 gallons
Water Conditions: 74-82° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025
Diet: Carnivore
Origin: Indo-Pacific, Fiji, Coral Sea
Family: Apogonidae
Species: Cardinalfish
Aquarium Type: Reef Compatible
Species Information
The Pajama Cardinalfish (Sphaeramia nematoptera) is a schooling species found living near coral reefs throughout the Coral Sea, Fiji and large areas of the western Indo-Pacific. Pajama Cardinalfish or as they are also known as Spotted Cardinalfish, have been a popular fish species with reef and community aquarium hobbyists for a long time.
Being a smaller fish species and native schooling species in the wild, it is best to keep this species in social groups of 5 or more individuals. Keeping the Pajama Cardinal in a schooling group will allow them to feel much more secure and comfortable within the aquarium environment; as well as, allowing them to exhibit their natural social hierarchy.
A group of will establish a strict hierarchy with a dominant male specimen leading the group. In addition to allowing the Pajama Cardinalfish to live as they would in nature, a group of these fish is an impressive site as they slowing swim about the reef in a tight group, which helps to accentuate their coloration and pattern.
Aquarium Care
Pajama Cardinalfish are best suited for reef aquariums with plenty of live rock and smaller peaceful fish species. However, they will also do well in FOLWR or community aquariums provided that their tank mates have a more peaceful disposition and there is a reasonable amount of live rock or coral decorations to provide them with a suitable habitat.
Pajama Cardinalfish should not be housed with larger more aggressive fish species, as they are slow moving and can easily fall prey to or be harassed by larger aggressive species. Tank mates to avoid keeping Pajama Cardinals with include: eels, sharks, groupers, triggers, hamlets, lionfish and other species of similar size and temperament.
Despite being nocturnal in the wild, Pajama Cardinalfish adapt well to aquarium life and will be active during daylight or lights on hours. It is highly recommended that hobbyists keep this species in a school of 5 or more individuals in order to allow them their natural social hierarchy, which will greatly increase their chances of thriving in the home aquarium environment.
Despite groups of Pajama Cardinalfish following a strict hierarchy, they do not use aggression to establish the dominant member of the group and instead utilize more of an internal election process within the group. This is markedly different from most other schooling species, where the dominant male uses aggression to establish himself within the group.
Feeding & Nutrition
Pajama Cardinalfish are carnivorous micro predators that feed on small crustaceans in their native coral reef habitats. However, they will quickly adjust to aquarium life and will readily feed on a variety of meaty based commercial foods including: flake, micro pellet, frozen and freeze-dried marine based meaty foods.
Being a naturally nocturnal species, hobbyists may have to acclimate them to feeding during the day time. This is best achieved by feeding them first thing in the morning before the bright aquarium lights are turned on. Lastly being a slow swimming species, the Pajama Cardinalfish will have a difficult time competing for food with many species of fish that feed aggressively.
Hobbyists should keep feeding concerns in mind when choosing suitable tank mates for the Pajama Cardinalfish or when adding this species to an existing aquarium.
Additional Photos