Here is a quick history. Feb 18, 2011 - Red Top Zebra added to tank currently consisting of 1- Albino Lab, 1-Ice Blue, 1-Eureka Peacock, and 1-red zebra. I was feeding the whole tank Hikari cichlid gold. March 7 - left for a week vacation, had friend feed fish 3 times during the week I was gone ( pre-measured the food and hid the package so no chance of overfeeding). March 15- returned from vacation all fish seemed well. Over the next couple of days noticed that the Red Top had no appetite so I purchased Algea tabs thinking that maybe the Red Top would eat that. The fish never would come out from under a rock that he always liked and still wouldn't eat. Today, dead. Water parameters tested out great. What happened? This all seemed to start while I was on Vacation.