Do tetras of different species school together?

You should easily be able to add a couple more Tetras depending on how many decor you have in your tank. And as for the schooling, they most likely would, they're instincts will tell them to school together and they will I have a 25 gallon tank with 5 Neon Tetras, 3 Red Belly X-Ray Tetras, a couple of Glolight Tetras which all school together, and 4 Lamp eye Tetras and 3 Buenos Aires Tetras which school together.