actually oscars like current. atleast everyone of 'em ive owned did. put the powerhead on a lower setting and you'll see that they'll actually prefere to be in the flowing water. i say keep it like that. but if it will cause the other fish not to feed normally then dont.
Man I kinda like it! Gives it a true riverene feel (I think thats the word Im lookin for). Would be great for some payara or Dorado or any other fish that like swift currents. A bit much for the Os though...
Our fish love strong currents. We change out 200 gallons at a time on our 300 gallon tank, and pump in the last 100 gallons very rapidly with the Hammerhead pump (5800 gph) on our mechanical filtration system. Our fish immediately head for the strongest, swiftest water to play. The oscars get tumbled around sometimes, but they can't resist it. Here's a video where Tommy, our Lutino Oscar goes surfing. Large Load Warning:
My experience when I had my oscars was the same as both videos show, they loved the currents. My filter puts out about 300gph, and that was where they always wanted to be. It gave them something to do other than fight over territories.