A balloonfish or 2?

This morning, I found a small balloonfish hiding under a ledge.  They are charming, shy little fish, that don't move very fast.  They belong to the porcupinefish family, and can puff up and/or erect their many spines to discourage predators from even trying to eat them. This fish was about 8 inches long, in about 15 feet of water.

Towards the end of our dive, I found another fish which is clearly in the same genus (Diodon) as the balloonfish, but lacks the dark spots.  It was about the same size as the first fish, but out in the open, resting on the bottom. My reef fish identification guide doesn't identify this fish, so I'm guessing that it is a close relative, a non-spotted balloonfish.