Pajama Cardinalfish

Sphaeramia nematoptera

Saltwater Fish Species Group: Cardinalfish Family: Apogonidae

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Water parameters

Temp 76-80 F Temperature

Maintaining a stable and appropriate temperature is critical for the survival of aquatic life.

pH 7.8 - 8.4 potential of Hydrogen

Measuring the acidity or alkalinity of water on a 0–14 scale, where 7 is neutral, 7 is alkaline.

NO3 1-20 ppm Nitrate

While less toxic than ammonia, high nitrate levels (above 40–80 ppm) are important to monitor because they can cause fish stress, stunted growth, and harmful algae blooms.

NO2 <0.0001 ppm Nitrite

It is a highly toxic, intermediate compound in the nitrogen cycle produced from broken-down ammonia

PO4 0.01 - 0.1 ppm Phosphate

It is essential for plant development but must be managed, as excess levels trigger nuisance algae blooms and inhibit coral calcification.

NH3 <0.1 ppm Ammonia

It is the primary killer of aquarium fish, causing gill damage, stress, and death

Ca 380 - 450 ppm Calcium

Supporting the growth, skeletal structure, and shell formation of corals, mollusks, crustaceans, and coralline algae

KH 8 - 12 dKH Alkalinity

It acts as a shield, neutralizing acids to prevent dangerous pH "crashes" that can harm fish, corals, and plants.

Mg 1200 - 1400 ppm Magnesium

It enables coral growth by supporting skeletal formation, assists in metabolic processes, and ensures that calcium is available for corals, clams, and coralline algae.

SG 1.023 - 1.026 SG Salinity

Essential for maintaining stable, natural water parameters, proper osmoregulation, and stress-free environments for marine fish and corals

ORP 250 - 400 mV Oxidation-Reduction Potential

A higher positive mV indicates clean, oxygen-rich water with high water quality, while low readings indicate high pollution.

About Pajama Cardinalfish

General information

The Pajama Cardinalfish is a small saltwater fish that typically grows to about 3 inches in length. They have a rounded body shape with distinctive black and white or red and white stripes. They are known for their peaceful nature and are a popular choice for beginner hobbyists.

Diet & nutrition

Pajama Cardinalfish are omnivores and will eat a variety of foods, including small crustaceans, plankton, and algae. They can be fed a mix of frozen or live foods, as well as high-quality flake or pellet foods.

Determining sex

It is difficult to determine the sex of Pajama Cardinalfish visually, as males and females look very similar. However, during breeding, males may exhibit slightly brighter colors and may also be slightly larger than females.

Breeding & spawning

Pajama Cardinalfish are egg-layers and can be bred in a home aquarium. Breeding pairs should be kept in a separate breeding tank and provided with plenty of hiding places. Once spawning occurs, the eggs will typically hatch in 2-3 days, and the fry will need to be fed small, frequent meals of baby brine shrimp or other suitable fry food.

Diseases

Pajama Cardinalfish are generally hardy and disease-resistant, but can be susceptible to common saltwater fish diseases such as marine ich and velvet. It is important to keep their environment clean and well-maintained to prevent the spread of disease.

Origination

Pajama Cardinalfish are native to the Indo-Pacific region, including the waters around Indonesia and the Philippines.

Cautions

Pajama Cardinalfish are generally considered safe for other tank inhabitants, but should be housed with other peaceful species of similar size. They may be intimidated by larger or more aggressive fish and could become stressed or bullied.

Acclimation process

It is important to acclimate Pajama Cardinalfish slowly to their new environment to avoid shock or stress. The drip acclimation method is recommended, which involves slowly adding water from the aquarium to the bag over a period of about 1-2 hours.

All photos

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