What is the best type of puffer fish to get?

Here's some information that might be of help. I have a friend who keeps them in his marine aquarium and here are some of our observations.

Stars and stripes puffers as well porcupine puffers are quite territorial (but not excessively so) and will enjoy living in larger tanks. They are not suited to a reef aquarium because they will eat snails, corals and other sessile organisms. They may require a lot of care and might not be suitable for a beginner.

The Fiji Blue Dot, on the other hand is much more friendly and are slightly hardier than the first two mentioned above. There should only be one per tank and they adapt well in smaller tanks as well. Since yours is 125 gallons, that should not be a problem. They are one of the most commonly available species.

The Saddle Valentini and Spotted Puffer will do well in fish-only aquariums and need experienced care as well.