Don't worry about the filter...I have two filters totaling 350 gph on my 28 gallon (the smaller is turned down slightly though) and none of my fish seem bothered. If in doubt check decorations like plants...if they move slightly (like a gentle breeze) then it should be okay...but if fish and plants are being whipped around obviously that's not good.
My guppy goes everywhere. I think tank layout, lighting, current, and inhabitants all kinda play a small role in where fish like to go... he now likes to try to school with the rasboras...