He's been in the tank much longer than the angel, but I wouldn't call either one as the aggressor. They just don't like each other for some reason, demonstrated by the "I'm bigger" acts. They both need open water space so I guess my 125 just isn't big enough for both. I could entertain keeping two together longer in the hopes of things working out, but just don't want to take the risk as both fish are highly valuable to me. I will let you know if this sale falls through.