I agree, need more info like the others requested. One comment that might help someone. I just set up a new 5 gallon Betta tank and kept getting a brown film across the top. When fed, my Betta would dart to the top and stop just short and then not eat. I figured out that it was the Betta Bulbs I had planted in the tank. Even though I had rinsed them thoroughly they were still putting off this awful brown film that Finley refused to touch, even to eat after 5 days. I removed the bulbs and the water is crystal clear now. So stop and think about EVERY single thing that has touched your water.

--Zambize