Apart from the banggai, there are also different species of the fish with different characteristics but they all share one common trait whereby they are generally adaptive and are not shy or easily startled like the tang or butterflyfish. Most of them are either black or gray color mix like the highfin cardinal while there are some which are overall orange like the Apogon cyanosoma and there is also the pajama type which has dotted spots. All the fish that form the cardinal group has the size of the eyes which are rather large relative to the body. Wild cardinals are known to reach 8 inches in size while those kept in captivity can be slightly smaller ranging from 5 to 7 inches only.
The aquarium setup for your pet should be at least 80 gallons and above. Cardinal can be mixed with other fish species, kept solitary or even buy them in bulk to form 6-8 in a group to create a single-species tank. Those that are grown in captivity can easily adjust to any established marine reef tank while those caught from the wild may take few weeks to adapt to the tank environment. Nevertheless, almost 80% of the wild fish are known to make it and survive. Cardinals are also known to resist common marine disease and they don't die for no apparent reason and as long as you carry out proper quarantine procedure before placing them to home aquariums, everything would be generally fine. When it comes to feeding, your pets is also not picky as they will readily accept invertebrates (which you provide constant supply by setting up an invertebrate tank) and high quality marine flakes.
Breeding cardinal fish is one of the most interesting subject to explore. They are known to be one of the marine species that will mouthbrood and take care of the young. Unlike freshwater cichlids having the mouthbrooding characteristics whereby the task is performed by the females, the saltwater male cardinals will do the incubating instead. Once the eggs are hatched and released from the mouth, you can start feeding the banggai fry with freshly hatched brine shrimp. One note of advice is that if you have an extra tank, try to remove the other fish species or else most of the young cardinals will end up getting eaten even with the attention of the male fish looking after them.
If you are a marine hobbyist with the intention to preserve the treasure of the ocean, you can also read up topic on Environmental considerations when setting up a marine reef tank. If you are a cardinal fan, you can also read up about the pajama species belonging to the same fish family.