we recently got a new betta, "chutney" (as he is a "kitchen" fish) he's in a 2 1/2 gal. bowl. He is my moms fish and she does water changes twice a week. We add this "betta safe" conditioner into his bowl. We notice lately that there is a filmy substance on the top of the bowl, could it be the conditioner since we don't have a filter?

There are a lot of theories about this...whatever it is, it happens in all unfiltered tanks. I've heard its protein in the water, betta spit, slime coat etc. I've noticed that it happens in my buckets of aging water if I leave it out too long so it might just be something in the water. I've also noticed and heard that if a betta is not feeling too well, sometimes the film on top can thicken.

Whatever it is, its normal and all of the unfiltered betta tanks have it. It won't do any harm, just look gross

I think Kissy is correct. When I had my crowntail in an unfiltered bowl his water would often accumilate a film on top

hmm that's odd as i get it too and my tank is filtered. although the filter does not ripple the surface so maybe it just occurs on the surface of still water.
I assumed it was something to do with the way they make bubble nests, you know how the bubbles are strong, i figured it was just the stuff they use to make/coat the bubbles spreading across the water surface in a slimey/oily film

The only time I ever get his is on bowls with left over plant sin them or bowls tha ti just left sitting. I think you may be feeding to much. How many times a day do you feed and how much do you feed?

i dont think i over feed him. i only feed him once a day, either a few (3-4) hikari micro pellets or one or two bits of bloodworm or brine shrimp. nothing on a sunday and one small piece of a pea once a week.

my mom feeds him twice a day. 3 pellets at each feeding =]

Is the bowl uncovered? If it is it may just be substances in the air like dust etc settling on the water. When I had my female in an uncovered bowl I had the same problem till I figured out it was dust.

yeh it's uncovered during the day, otherwise he's be in the dark the whole time maybe it's just stuff in the air then. i always assumed it was what they use to make the bubbles so strong as it seems to occur about the same time as he starts blowing bubble nests a few days after a water change

I had a crowntail once that would blow bubbles right when the water needed changing.