it depends on the species,there are like 4 that do quite well in a tenYou can't just put a Cory in a ten gallon. Cories need to be in groups of at least 4. One Cory will not do well in a 10 gallon alone. Cories need at LEAST around 30 gallons.
AquaKai said:The dwarf cories would work in a 10 gallon tank, and yes do have around 5.