African Chichlid

Question
I have had an 55 gallon tank for about 15 years.  About 18 months ago I switched to African Cichlids.  Everything was fine until my water heater broke in the tank.  I didn't notice until the water was 70 degrees.  I immediately replaced it, but I started having dead fish one or two every day.  I noticed the fish had black patches on the face.  I replaced the water, but the last of my fish died this morning.  I now have 2 cat fish and that is all.  Before I invest in more fish, I was wondering if you think it was the cold, or the exposed heater eliments or what that may have caused their death.  

I appreciate your help on this matter.

Clara

Answer
Hi Clara,
I don't think it was he cold, because the temperature must have gone down slowly.  You may have brought the temperature up too quickly.  When bringing up the temperature, we must do this very slowly.  One degree each day until you reach the right temperature.  Bringing up the temperature of the water too fast, can be deadly.  The same goes for bringing it down too fast, but in a 55 gallon tank, I don't think the water went down quickly.  Either way, it is very bad for fish.
Lynda