I've had two Angels since they were tiny, last summer in a 29 gallon tank, slow water flow, tall plants, & just a few well-tolerated tank mates. About a month or so ago they became aggressive with each other. Not always. They would fool me. Sometimes they would glide along peacefully, then bam! So, I researched and learned due to their maturity & large size, transfer to 55 gallon. Which I did. I also added a few more fish. All happy for a week or so then aggressive behavior began again, only much worse. I gave them a few days to sort it out to no avail. Now, I have one in the 29 gallon & one in the 55 gallon (each. w other tank mates). Question: I am reading that Angels do well on their own, but is this the case after they've been raised as a pair?