All Cichids Diedwithin 1 hour...

Question
Hi,
My husband set up a 150 gallon Aquarium with 25 rare Cichlids,6 clown Loaches and 2 Plecos.. We had this tank up and running since July... We have had no deaths and all of a sudden on 10-6-07 i received a phone call from a employer that the fish were dying fast... Well my husband was out sick so he stopped in earlier to sign checks and he  fed fish and came home..Well when i got there i fished out the dead fish... and  caught several others who also died within 5 minutes of catching them.I ran tests and everything was fine..I was so upset i went to petsmart they tested the water and it was also fine.My question is i think our fish were poisened.Is there anyone who could test the water (expensive or not) to find out what is in the water that killed the the fish?Or do you know anything that would knock of all fish within 1 hour..

Answer
Who has been feeding them?  Is it possible that they were overfed?  I don't really know of anyone that could test the water except maybe a vet that deals in exotic animals.  You could also take some of the dead fish in for an autopsy at a vet. Those are my only suggestions and I am sorry for your loss.  What kind of cichlids were they? Even in a 150 gallon tank 25 cichlids is quite a few for a territorial species.  Is it possibe that they killed each other?