Angel Behavior

[svolk]

I currently only have 2 angels in my community tank, along with guppies, mollies, 2 balas, a betta, and a pleco. I orginally had 4 angels, but 2 died. Besides the balas, the angels were the last ones added to the tank, and they have never been aggressive/territorial towards each other or anyone else in the tank.

My 2 angels have been in the tank, peacefully, for almost 3 months now. Last night I noticed both of the angels picking on each other, occassionally biting the other at various time. Maybe they have been doing this all along, but I have never seen them behave like this up until now.

My husband and I assumed that since they have been getting along fine without more angels that they would continue to do so. Is this typical for their behavior to change abruptly? Do we need to add more angels to the mix?

Initially I thought I saw just the one angel picking on the other, so I thought that there was something to do with breeding going on, such as the female was not ready to spawn..? But then I noticed that it was both of them doing the biting. Or could it be that I have 2 males or 2 females and that mix doesn't do well..?

As you can tell, I'm full of questions..

[Lisachromis]

How big of a tank do you have? It's very likely you've filled your tank to capacity considering that you have a Bala shark.

[svolk]

I have a 55 gal. and I know that the balas will need to be moved. We currently saving up for a 100 gal., we figure we can get one within the next 6 months.

Last night I was observing that tank again for awhile, and it seemed that it was just the one angel being aggressive. The other one would try to come near him/her, and the aggressive one would go right up and bite him! They used to hang out together all the time..