| Re: what happened?
Hey Tweaks!
Based upon what you said in another thread about your convicts becoming aggressive enough to attack your hand, IME this is not all that unheard of and might not be a sign of a bigger issue at all. Granted, I have never kept convicts or any of your other fish for that matter, but like I said, I have read/heard/witnessed the same thing in other fish. In fact, even though they are not freshwater fish, my very small clownfish attack me furiously if I get too close to their anemone or in its vicinity. My point being that it may be possible that your convicts are defending their territory and/or some eggs. It may also be possible that the reason they are so overly protective or aggressive is because they are constantly defending against another fish in the tank such as, if I remember correctly, the pearl eartheater you keep with them...which I noticed are labeled as being 'aggressive' in at least the few species profiles I just looked at.
Otherwise, perhaps this is a similar situation as Oscars are relatively well known to do in that they will form harmonious mated pairs for a long time, but suddenly refuse to get along at all. Like I said, I dont know much about any of your fish so I am just throwing ideas out there which you might want to explore. | 
