one fish died not sure what to do with the other

Question
hi i bought 2 goldfish about 2 years ago now one was a yellowy goldfish and the other more orange. as the fish began to grow the orange one got bigger than the yellow one which didnt seem to be growing as fast. last week the filter broke but the fish seemed fine and swimming around happily as usual, but 2day i noticed my smaller yellow fish had died and i dont know why. the orange fish is now close to the bottom of the tank swimming very slowly, it almost seems sad. there are some very small blue dots on the glass of the tank but i thought it was just bacteria. i now dont know what to do with the other fish because i dont want to buy any more to give it company due to the upset of my little brother when this one died. my boyfriend does however have a pond with a few fish in it 2 of which are goldfish. should i put my fish in there, im a bit worried it will be too cold as this fish has only ever been a house fish. also if it does have any disease which i never noticed in my other fish as its death was quite sudden, i dont want it to infect my boyfriends pond fish. help what is best for my fish?

Answer
Hi Rebecca,
  The goldfish does not need a companion.  He is likely swimming slowly because when the other fish died, it polluted the water.  You need to immmediately change about 25% of the water in the tank and then do the same thing again tommorrow.  That should help a lot.   

-- Ron
  rcoleman@cichlidresearch.com
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