I thought from reading his Wikipedia page (and looking at his face) that he was probably a gentile, whose mother cucked his jew stepdad. But looking at his mother and biological father, they both look pretty jewy, especially his mother.
You do have to be careful just looking at names, though. Some German and Scandinavian names sound jewish, but are not. Some German names are shared by both jews and gentiles, so a gentile may have a "jewish" name and be a gentile (Alfred Rosenberg is a good example). Some celebrities take stage names that are jewish - Zachary Levi was born Zachary Pugh, for example. And then there are gentiles adopted by jews, such as Lauren Cohan.
It seems to me that gentiles raised by jews don't tend to end up very jewy. These people are a good argument for the Jewish Problem being mostly biological. Andrew Breitbart is the major example that comes to mind. He was a gentile raised by jews, but grew up to be not very jewy at all, and in many ways a thorn in the jews' sides.
To the point at hand, though, it looks like "Bloom" is an exclusively jewish name. My money is on this Fields guy being a mischling - jew mom, gentile dad. That's what he looks like to me.
