thin film on the top of the water? what is it?
- Thread starter chee
- Start date
Dr Awkward (above), got it right. The film you are seeing is called a "biofilm" and is a combination of bacteria and organic matter much of which comes from the food you feed the fish and if there's any decaying matter, such as plant leaves. It is harmless and will not hurt anything.
CrimsonBlush
Attemping to post rather than lurk
I use surface agitation to keep mine at a minimum. I rarely see it anymore. But yeah, it's never harmed my fish. 
OK people -- the film you are asking about IS a biofilm -- it will not hurt the fish and you don't have to stress out over it -- it is natural to these sorts of bio environments such as fish tanks, ponds, lakes, etc. Here you go:
A biofilm is an aggregate of microorganisms in which cells are stuck to each other and/or to a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance (EPS). Biofilm EPS, which is also referred to as "slime," is a polymeric jumble of DNA, proteins and polysaccharides. Biofilms may form on living or non-living surfaces, and represent a prevalent mode of microbial life in natural, industrial and hospital settings.[1] The cells of a microorganism growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which by contrast, are single-cells that may float or swim in a liquid medium. Microbes form a biofilm in response to many factors.
Regards
A biofilm is an aggregate of microorganisms in which cells are stuck to each other and/or to a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance (EPS). Biofilm EPS, which is also referred to as "slime," is a polymeric jumble of DNA, proteins and polysaccharides. Biofilms may form on living or non-living surfaces, and represent a prevalent mode of microbial life in natural, industrial and hospital settings.[1] The cells of a microorganism growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which by contrast, are single-cells that may float or swim in a liquid medium. Microbes form a biofilm in response to many factors.
Regards
I have the bio-film right out of the tap. Whenever I fill up a new tank (even a bare bottom), or do a water change, I immediately see the film. So in my case, it has nothing to do with the food I feed my fish.
My film is relative thick with a dark gray appearance. I can't believe that is harmless. I have skimmers running in all my tanks.
My film is relative thick with a dark gray appearance. I can't believe that is harmless. I have skimmers running in all my tanks.
