No, you cannot keep two neon tetras. Neon tetras are best kept in schools of a minimum of six and may die of stress if you don’t keep enough of them in your tank. The more neon tetras you keep, the better their standard of living will be.
Ten neon tetras are the ideal number you want to keep in your tank. Also, make sure to keep a clean tank, with the right conditions for your neon tetra fish.