URGENT! Oscar acting weak

Question
Hey Ron sorry for the hassle but I just purchased an Oscar, about 10cm/4".
The place I got him from was very dirty, the water in his bag was yellowy so when I acclimated him for about 15 minutes I mixed some of my water in and then poured all the water out and caught him in a net. THEN I placed him in my tank. Almost instantly he he plummeted to the tank floor and just layed there, spooked the hell outta me. All my PH, Nitrites, Nitrates are all in order but the water was quite cold about 20c/68f. The heater didn't warm the water quite enough so in a desperate attempt I poured warm water in about 4 litres and added water conditioner. The water was brought back up to 24c/75f but still no sign of improvement.

If you can tell me why hes acting like this or how I can prevent him from possibly dying it would be greatly appreciated.

Thanks again Tim.
Thanks again Tim.

Answer
Hi Tim,
  Sudden water changes of any kind (temperature, pH, even nitrates) are not good.  You need to change things slowly for a fish. In some ways, "bad water" is better than rapidly changing a fish to "good water" -- you ultimately want the fish to be in good water, but make the change gradually (over a few hours) to give the fish a chance to adjust to the change, otherwise the fish will experience "shock".  

 I hope that your oscar is okay now.

-- Ron Coleman
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>