Slime And Film Over Water

[msasa19]

i set up my betta tank with mature media about a months ago, i change 30% of the water a week. everytime i do it there is a lot of slimy film floating about, and i mean a lot, also on the top of the water there is a strange film and if i put my finger on it, it seperates, what is it, i only have one real plant in there, not sure what it is though.
 
no matter how many waater changes i do it doesnt make a difference it just comes back!
 
 
what is it?

 

[Livewire88]

Hello, 
 
I assume you have little or no surface movement which is allowing the oily looking build up on the surface of your water. 
As it is your Betta tank you likely want to keep the flow low so that the Betta is comfortable and this is going to be the problem with your battle with the surface slime. 
 
Feeding high protein foods (which your Betta will love) may make the issue worse if any of the food is left uneaten, I had the same issue with my Arc60 tank due to minimal surface movement due to using pressurized Co2, I ended up purchasing one of these; 
 

 
It skims the surface of the water and removes any build up so I now no longer have the problem. The only thing is this may not be an option for you because the Betta may not like the extra flow caused by the skimmer. if you have no other option use a cup and put it in you tank upright and tilt it slightly so it sucks the surface of the water into the cup, do this till all the scum has been removed ans top the tank back up with fresh treated water. You may have to do this daily to keep on top of the scum. 
 
Hope this info helps

 

[gwd]

Hi,
I had the same problem in my betta tank. I put an air stone in. I put it at the surface of the water (about an inch deep) which worked perfectly! Helped keep the top of the water moving = no oily slime coat , yet did not disturb the water to much to bother my betta.

 

[msasa19]

thanks for that, all seems so obvious now i think about it! will put an air stone in and move the spray bar

 

[DrRob]

Livewire's suggestion I've seen run with a timer, so it only runs for a few minutes a day and is reported to work very well.
 
Otherwise the oily film is sometimes off you. Oils from your skin, moisturiser and other soap type products or sun lotions can be to blame. Beyond that, the high protein food is indeed usually the issue.
 
The really low tech solution is to lie a piece of kitchen roll or newspaper on the surface and then lift off again.

 

[mark4785]

I have experienced this exact issue and the tank water was completely devoid of oxygen. It came about despite the fact that I had NOT put any food into the aquarium so it wasn't derived from the food. I associate it with a lack of filter maintenance and/or something from the environment getting into the aquarium and replicating. My aquarium is an open-top so thats why I believe the latter.
 
The only way I got rid of the floating film and replicating filter gunk (which was a orange slime; not sure if OP has this too?) was to add about 5k of salt to the aquarium and a slight amount of bleach.