Question
QUESTION: Hi we have just accidently left the hose on all night so the 7 adult Koy fish are now in a pond full of tap water.
They are swimming really slow and not happy - is there anything we can do ?

ANSWER: Sulfer salt in liquid form (dechlorinator) is the only way to quickly react the chloramine out of the water.  What kills the fish is a chlorine poisoning, so once the poisoning takes effect it is impossible to reverse the effects.  Best of luck.

---------- FOLLOW-UP ----------

QUESTION: Thankyou so much !!! How long do you think we have to do this ?

Answer
I do not mean to sound negative, but there's usually not a window of more than a few hours.  Chlorine poisoning can easily kill within five hours.  I'm surprised they all survived but perhaps it is a good sign that that will go on to live.  It is never too late to dechlorinate (please, pardon the rhyme) and you might even save them.