If you are looking for active, schooling marine fish to grace your home aquarium, then the Pajama Cardinalfish (Scientific name: Sphaeramia nematoptera) would be perfect for your plan. Being relatively inexpensive, you can get any aquarium-bred fine specimen for under $20 as these hardy, reef-safe pet fish will certainly worth any price that you paid for. The fish can become your long-lasting companion provided that you understand and know well about their requirements to provide the best care that they deserve. Even though they require very little attention when housed in an aged and well-established tank, sometimes even the most experienced aquarist will find it hard to comprehend what went wrong to their prized possession. Let us look at every detail about this tropical fish.
Appearance and Look
Pajama cardinal although may look dull to some but in a nicely-decorated saltwater fish tank (as shown in the picture), their color contrast seems to project out and will become clearer especially when they are swimming among shades of darker backdrop. The species is easily recognizable not only by their shape but you can also tell them apart from their color. One thing that you will find unique about the fish is that near the head region, it is generally yellowish, then after the gill you will find a single black vertical band located almost at the center of the body and towards their rear, you can see a number of brownish faint dots appearing until the tailfin. Another significant feature you will find present on the pajama cardinal is the two pointy dorsal fins that seem to be their unique signature. All I can say is that if you happen to see one, you will know it’s them, even without looking at the identification tag displayed on the fish tank.
Aquarium Food and Water Quality
Care requirements for cardinalfish would the same like most of the tropical marine fish. There is nothing special that you will need to particularly watch out for. However, one aspect based on my experience dealing with them is to be sensitive with your pH control as a sudden drop can be quite devastating for them. Pajama cardinals are known to be susceptible to diseases such as bloating when fed with certain commercially prepared fish food and just like any other marine dwellers, it would be best that you have a well-established reef tank where there are presence of microscopic microorganisms to supplement their diet and keep them healthy. Newly acquired cardinals introduced to a different tank setup may not even eat and sometimes, they will take quite a long time to adjust to the new environment. It is recommended that you provide some artificial cave as hiding space as these nocturnal fish seems to like it there. If you have a tank that simulate a day and night cycle, you will also notice that they are particularly active when the lights are out. Also don’t forget to keep a close watch on the temperature because being a tropical species that are found mostly off the coast of Indonesia from the Java island to Sulawesi up to Papua New Guinea, it is wise that you provide the condition almost close to the natural habitat where their ancestors live and proliferate.
Compatibility with other Marine Fish
“Peaceful” would be the choice of word best use to describe the species. It is very rare to find pajama cardinal developing social conflict with the other fishes. They are suited living in a community environment comprising not only fish species from their own cardinal family but they will also get along pretty well with some other distant marine cousins like the clownfish and firefish. A basic rule of thumb, avoid keeping them with other larger companions especially those with predatory nature like the hawkfish. In general, they are invertebrate-safe but that only remain true provided that you don’t have tiny invertebrate so small like the mini shrimps that the fish will easily fit these creatures into their mouth.
Breeding little cardinal fry
Pajama cardinalfish tends to readily breed when kept in perfect living condition and their numbers will multiply if you have a large tank that is generally under-stocked. This will ensure that the young has plenty of food to feed on and most important having enough hiding space to avoid themselves from being eaten by the other fish and even from their own parents. Most aquarists advocate separating the young and then feeding them with live brine shrimp to ensure higher mortality rate, but however, most that successfully raise and care for the fry until they reach adulthood will tell you that it is not even necessary to do so. If you hope to increase incidences of the fish spawning on their own, make sure that your pets are kept in groups or school of more than 6 individually matured fish to have higher chances of mating. If everything else fails, it’s time to recall what you have done and investigate what went wrong because perfectly well-cared cardinal pairs should breed on their own without your intervention.
