My betta seems distressed by his filter

[Cay23]

I've had my betta for a few weeks and he's been living in a approx. 2 litre tank with plants, gravel, the usual. However, I've just moved him to a larger tank (30L or 8 gallons) where there's a heater and filter, but he doesn't seem to like the filter much.
It's blowing across the back wall of the tank and whenever he goes for a breathe he gets knocked around in the outlet stream and then swims off madly, with his gills opening and closing rapidly (it looks like the equivalent of a person gasping for air).
Is this just because he's used to stagnant water or because the filter is too powerful? At the moment I've got the filter off, but will need it on later as I want to keep a community tank (it'll have a maximum 5 other fish).
Any suggestions? Is there a particularly good brand of filter to use?
Thanks!

[Mister Sparkle]

Some people make special adjustments to filters to try to block the flow.

Personally, I'm a big fan of the sponge filter. Here's a good one for your size aquarium: Lee's Triangle. Very little water movement from these.

[Alienbetta1]

I turned off my fishes filter and he seems so much happier.

[1fish2fish]

A sponge filter is a great option. I prefer power filters myself (they just work well for my current situation). What kind of filter do you have? I might know a couple tricks to lower the flow if you don't want to switch to a sponge.