fish tank

Question
hi i bought a second hand tank with filter basically everything u you need to start a tank up with ,ive had a tank before and never had problems ,but since buying this tank ive lost almost all my fish ,im at a loss as what to do ,ive done water changes had the water tested and all seemed ok ,although i noticed some of my fish had cotton wool like balls on them also some of my ornaments seemed to turn orange ,im about to empty my tank and start again ,can you please give me some advice so this doesnt happen again

Answer
Hi Lisa,
  Where are you getting your fish?  I strongly encourage you to purchase your fish at a good fish store to ensure that they are disease free.  

  It is important when starting a fish tank that you set the tank up, then wait several days, then add only a couple of fish.  Do not add more fish for several weeks, until the tank balances out, or "cycles" as we say.  

-- Ron
  rcoleman@cichlidresearch.com
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