I bet our old tetra was super happy to see a bunch of new, young tetras in the tank. It took a few days for them to start hanging out together, however. The new tetras were not sure about him at first, and would swim all over the tank. The old guy was too tired to chase them and just hang out in his favorite plant. Eventually they warmed up, however.
Luckily it also didn't take them too long to get over their fears of all the other fish in the tank.