I had an incident with my female dempsey wiping the floor with my f1 chocolate and my paratilapia polleni. ended up taking it out, but eventually the chocolate perished as it was recovering from previous illness
I had 4x 1" convicts sold to me as 'community fish' I put them in my tank of mollies, neons & bristlenose cats. It was only a couple of days before I noticed a decrease in population (everything but the cons vanished within a month) The 4 cons seemed happy for another couple of months then 2 paired up and beat the crap out of the other 2. My solution - I gave the unpaired cons away, the paired ones have the tank to themselves...
Last time I believe an LFS without doing homework first - I'd hate to see what they would classify as an aggressive fish!
