There are Fish!

I tried putting 20 goldfish in my fish tank several months ago and as far as I could see at the time, there were no survivors.  Yesterday while redoing some plumbing on the fish tank I discovered two healthy gold fish.  I havent really fed them, but there is algae

growing in the tank and I guess they were doing fine as cold water vegetarians.  Someone at the aquaponics association meeting told me that it might be disease and not water quality that killed the initial batch of fish.  Apparently they were right.  Go figure.