metriaclima zebra died ?

[rtenzo02]

I've had my cichlid tank running for about 3 months now and everything has been running just fine until today. My metriaclima zebra has died. I first noticed about 4 days ago it had been hiding in the rocks and caves and hadn't been comming out to eat or explore like it normaly did. It was one of the smaller cichlids in the tank but known to be the most aggresive of the species i keep. About 2 days before i noticed this abnormal behavior i added these rocks after they boiled for about 20 minutes. Also i added cleaned play sand and did about a 80% water change at the same time. The other cichlids still eat and still appear to be healthy. Hoping someone can tell me what type of rocks these are so if there the problem I can remove them from the tank. the last few nights i have unplugged the heater cus it seems to be stuck on 82 degree. When i woke up the temp had dropped to about 74 overnight. Like I mentioned the other fish seem to be ok. i just checked the ph and chlorine and ammonia levels after removing the dead fish. Any suggestions would help me out ?
http://i153.photobucket.com/albums/s228/rtenzo02/Mobile%20Uploads/1258347171.jpg

[rtenzo02]

sorry the ph was 7.6 and the chlorine and ammonia both tested 0

[James123]

The rocks are called lava rocks and there man made and in my opinion they are really not a good choice for a cichlid aquarium because of the very rough texture which is hard on the skin of fish. You would be much better of with almost any kind of rocks that would be much better, also I don't understand why you boiled the rocks, a little bleach in a bucket with water for half hour with a very good rinse using the bucket is fine. I can't say for sure what killed your fish but if it was unaccustomed to a large water change that you did that may be the culprit. Heaters never correspond to there set point temperature so always use a good thermometer to adjust your temperature accordingly. You will be better chucking that old heater if in doubt of reliability. Peace out

[rtenzo02]

I boiled the rock because it has been in my backyard for the past 4 years, by boiling the water I was killing anything that could be harmful to the fish.