Thats not the one that was on Planet Earth. The one on Planet earth does not have a taperd down mouth. This is a different type that most likely feeds on small crustations and inverts.
they USUALLY don't do well at all in captivity they are hard to get to eat
but when you get one that eats well for you they can get up to 16in. I believe and I do know that they tend to be fairly territorial thats with anyfish not just with other dolphins