Goldfish dying

Question
I have a problem of my goldfish dying after a week or two.
I buy from a reputable store and  the water tests ok.
I do not over feed them and I change the water weekly.
They are fine for a few days and then stay on or near the bottom
and then .... The only thing that I can think of is that they
are being fed tropical flakes as opposed to goldfish flakes,but I can't see that being the problem. Any thoughts ?

Answer
Hi Ron,
   Tropical flake food is better than goldfish food so that shouldn't be a problem. I assume that you are not buying "feeder goldfish", right?  
   Also, be sure that the water is not too warm, they don't do well in water above the mid-70's or so; they are not tropical fish.

-- Ron C.
  rcoleman@cichlidresearch.com
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