That is definitely a snapper. He looks quite young, how long is he? He also looks like a male with the long looking tail. Honestly he may act differently because he is young. I had a snapper that was the size of a quarter and he loved to swim around and he would attack any food I gave him. He didn't start developing other characteristics until he was older ( a few years older). He didnt develop "snapping" until one years old. Does his shell shed about everyday and produce more spikes and crevices?