Okay so I got home from school this morning, plopped down in my chair, and spun it around to see my angelfish locking jaws. I was surprised since I've never seen this behavior before. I've heard it can either be a sign of a pair or a sign of aggression. As is, the black angelfish has no injuries and the marble one has a bent bottom fin (He tries to fit under a bridge too small for him, might have to remove it). So basically, no injuries that would indicate fighting. However, the black angel has recently exploded in size, catching up to the marble fish who was always the bigger one. Is there any way for me to tell whether this is fighting or mating? Thanks.