Antimatter, while theoretically ideal for interstellar travel, currently isn’t practical.

I’m not saying we won’t get there, but it’s a very far reaching goal.

First we need a reliable (and CHEAP!) way to manufacture it.

Then we need to be able to contain it for long periods of time. I believe the record is currently a few minutes.

Then we need to have some mechanism that will use the energy from the reaction and convert it into propulsion.

Anti-matter as a fuel is a long way off, unless several breakthroughs are made.