weekly Layton puzzle #009

Professor Layton and the Curious Village puzzle 053

requested by @laytonwithagun

Fish Thief

When you weren't looking, someone came by and gobbled up your fish dinner. The three brothers near the scene of this dastardly crime had this to say:

A: "Me? Oh yeah, I ate it. It was good too!"

B: "I saw A eat that fish right up!"

C: "B and I didn't eat that fish."

One of these three brothers is lying to you.

But which one is it?