Are Cardinalfish Schooling?

[tuggerlake26]

I keep reading conflicting articles: some have said cardinalfish like to school, others say in an aquarium it's usually best to keep one or two. For anything under a 40 gallon tank, would it be best to just keep a single one? Does it differ by species?

 

[FinalFins]

I don't believe banggii or pajama cardinals are schooling fish, but they can be housed in numbers.