This is one of my favorite cichlids to keep.
That said, it can be very territorial once it hits maturity (@ 7"), and needs a large space.
To keep with other cichlids, a 300 gal tank is probably the smallest it will work in.
In nature it is usually found in fast flowing areas, walls of moving water.
This (along with too small a tank, mine was 150gals) may be why it became so belligerent, I doubt I had a strong enough flow to use up their excess energy, and it was redirected at other tank mates.
At the time I was using a 1500 GPH pump to circulate the tank thru its sump, (IMO not sufficient movement).
Once the alpha argentea, hit 7 " it started killing all other cichlids in the tank (including other argentea).
It had a 13" dovii, pinned in an upper corner, and I finally gave the argentea its own tank to save the others.
Until it hit 7" it was quite shy, but it turned to Mr Hyde almost over night.
