How many fish can a ten-gallon tank hold?

Sorry, A ten gallon is too small for tetras. They are very sensative fish that can not tolerate the unstable water conditions that occur in small tanks. you mean zebra danios? they are extremely active fish and need a 20 gallon tank minimum. Most Cory cats get too big for a ten gallon. Dwarf cory cats need 20 gallons or more, regular cory cats need 30 gallons or more. You could get a school of 6 pygmy cory cats but they are not really a bigginer fish. Most cories do better in soft water with a ph of 7.0 or lower. The only other fish that could go with them in a ten gallon is a betta.