What Is This Oily Film?

Discussion in 'Freshwater Beginners' started by Kat129, Apr 19, 2017.

  1. Kat129Valued MemberMember

    Hi everyone.

    After a failed attempt at fishkeeping a few years ago I am attempting to set up a new tank. Trying to do it properly this time so I end up with nice healthy fish.

    I have a 64l tank that I have started running a fishless cycle in. I am on day 3 with ammonia at 4ppm.

    Today I have noticed an oily film on the top of my tank. What is it and will it go away when my tank is further along on its cycle?

    My tank contains 3 pieces of wood (that have turned the water brown but that is ok) and 8 plants. No fish yet.

    I added Interpet Tapsafe when I added the water and Filterstart on days 1 and 3.

    Any advice gratefully received.

    Thank you
  2. Summer22Valued MemberMember

    I've seen people ask this very same question before and my tanks have it too. Someone said that it's just the oil from your fingers. Then someone else said it could have come from the new filter added if it wasn't rinsed or something. I choose to side with "oil from fingers". What ever it is, it is totally harmless, and for me, it has never gone away in the year I've kept fish.

  3. PunkinWell Known MemberMember

    I've had that happen to me when I did not have enough surface agitation. If you increase the flow of your filter (depending on what kind you have), it should go away. Mine was just from oil in fish food, etc. The surface of the water should have some movement, the more the better, especially for oxygen exchange. And in turn, the more agitation, the less oil film you should see.

  4. NanologistWell Known MemberMember

    I call it "bio-film". Just proteins and organic materials from the food, fish waste and what not. I had it in my tank as well and it started getting thick enough to where I was concerned about my Betta having to breathe through it, so I created a little scoop for my filter to direct the water coming out towards the surface to agitate it much more. Now it only collects in one corner where some of the plants slow down the water movement.

  5. PunkinWell Known MemberMember

    Agree, I have a tiny corner behind the heater that doesn't move alot so there is a little triangle of film there, but the rest is moving. :)
  6. 2211NighthawkFishlore VIPMember

    Agreed. Get the surface water moving a bit more and it will go away.
  7. Kat129Valued MemberMember

    Thank you everyone. Is it still likely to be biofilm if I don't have any fish yet? Just gravel, wood and plants in my tank at the moment.
  8. NanologistWell Known MemberMember

    Yeah, most likely. Can you get a pic?

    What are you using to cycle the tank?

    Any decomposing organic material will do it. It's from the wood, plants and the bacteria that's growing.

    Here's a great explanation:  
  9. BodescaNew MemberMember

    I hate having the biofilm. I make sure there is enough water movement to prevent it.
  10. Kat129Valued MemberMember

    Can't get the angle right to see the film on the water so this is the best pic I can get. Sorry.
  11. NanologistWell Known MemberMember

    Yeah, that's biofilm for sure. Not much of a problem and means your tank is growing bacteria, which is great. Most people just don't like the sight of it, but also if it gets too thick it hinders oxygen/CO2 transfer to the water. Like we mentioned, just get more surface agitation from your filter or a powerhead and it won't be able to collect.
  12. PunkinWell Known MemberMember

    Very nice looking tank, too. :)
  13. NanologistWell Known MemberMember

    Agreed! Can't wait for it to cycle and get some fish in it. Looking forward to more pics in the future.
  14. Kat129Valued MemberMember

    Thank you. I was given some mature fiter media from a friend yesterday so hoping it won't take too much longer to seed and cycle. Just need to work out what fish to put in it now!

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