Got a filter- should I have?

[SquishyFish]

My betta is a rescue fish (Squishy) whom I bought from a florist because he seemed miserable in a sad, cramped little cup.

He's in a fish mansion now- 2 gallons, big plant (he's actually taken on its colorings) and a Spongebob Pineapple he LOVES (though I read some warnings about them on the other posts?!)

Anyway, he's really thriving- grown to twice the size since March, maybe more. However my fiance and I have been saying we need to get him a filter-- we clean the tank once a week but thought it would help. I had noticed over the summer that when he was near the AC he seemed aggitated, so we moved him. My concern was that a filter would have the same maddening noise level for him.

I can't tell if we did a good thing or a bad thing. He used to make "love bubbles" at the top of the tank but he can't now, and he stares at the filter like he's trying to figure out what it is.

I just got paranoid and shut it off. He's hiding in the pineapple. Thoughts?

[sainthogan]

A filter isn't a bad thing unless the water flow is too strong for him. Both my tanks have filters and they don't bother my fish, in fact, they freak if they're not on. Depending on the type of filter you have, you can adjust the flow or baffle it with a sponge or water bottle to keep the flow from being too strong for him.
My thought about the ac bothering him, does he have a heater? If he doesn't perhaps it was bothering him because he was getting too cold.