Successful Keeping Apogon Cardinalfish
Cardinal fishes or Apogonidae, are a family of ray-finned fishes. They are found in the Atlantic, Indian, and Pacific oceans. They are mostly marine species. A handful of species are kept in the aquarium and are popular as small, peaceful, and colorful fish.
They are generally small fish, with most species being less than 4″, and are often brightly colored. They are distinguished by their large mouths, and the division of the dorsal fin into two separate fins. Most species live in tropical or subtropical waters, where they inhabit coral reefs and lagoons.
Cardinal fish are nocturnal carnivorous fish, but when established in the aquarium they will become more and more active during the day, although they tend to become more active during the last stages of the lightcycle (moonlight etc.). Their large eyes are a clear sign of their nocturnal life.
Because they are carnivorous fish, they have to be fed with meaty foods like artemia, mysis or even krill. Their mouth is adapted to relatively large prey, so don’t worry when you think that mysis may be too large for them. After they are used to life in captivity they will also accept flake and granular foods. I try to feed them at least a few times during the day, because I think it is better for the fish to feed them smaller quantities more often. In nature they also eat small quantities during the whole day, and if it’s possible you want to try to simulate that.
Because cardinal fish are small (probably tasty) fish, they will become a food source for many larger carnivorous fish on the reefs. That’s why they tend to be shy, and like to have a hide out in short distance. Large, branching SPS colonies, or nooks and crannies in the rocks can provide enough shelter.
After a while in the tank they will become less shy, and retreat not as often as just introduced fish. Luckily they will stay shy enough to continue to form a tight school, even after years in the aquarium. That’s why I prefer this fish more then Chromis species for example. The school is more compact, giving it a much more impressive appearance.
Of course there are also a few downsides on the Apogon species. They’re known as hard shippers, which means that the loss during shipping can be high, sometimes even 100%. Next to that they can be difficult to accept frozen and dry foods in the beginning. Because these small fish don’t have a lot of energy reserves, this can also become fatal.
I do have a few suggestions to make shipping much more successful, without too many loss during shipping. First, acclimatisation at the LFS or wholesaler is very important. During their import from the Indo-Pacific or Australia (most popular species) they have become very stressed, and need to recover for at least some days. When purchasing in the LFS, make sure the fish are there for at least a few days, and accepting frozen foods.
When you’re able to transport the fish from the LFS or wholesale yourself, you can also prevent large losses by transporting the fish with at least a few together. Never pack the fish alone in a bag, this will be very stressful. This are schooling fish, and the presence of at least a few others will drastically reduce stress during transport.
Another thing is water quality of the transport water. Try to transport the fish in as much water as possible, the rest of the bag filled with pure O2 gas.
I’m currently experimenting with an Ammonia binding solution from Prodibio, called “stop Ammo”. This is normally used during the startup of a reef tank to help it cycle. Binding and with it reducing the Ammonia level in the transport water can also help to prevent excessive loss. I’m experimenting with it myself right now, so I’ll have more about this later. I’m also experimenting with small bags of high quality GAC (Granular Activated Carbon) to take up harmful organic compounds.