Oliy residue on top of water

Hey Dirk

Whats the oily reisdue that appears on the top of the water in our tanks? Protien?

If you remove it, it just returns.

Any risks?
Is there a way of not getting this to occour?

 

I remember reading somewhere that if you have dead fish in your tank, there could be a oily type residue on top of the water. You missing any fish lately?

 

anyone with cream on their hands?

 

It's a type of algea.

 

I heard it's from not enough surface agitation... Can't remember where from though

 

Its a protein film. What are you feeding?

If you get enough surface circulation/agitation it should go away

 

Hi Gilbert,

This is caused by a bacterial microfilm. It can be the result of feeding but what has happened is that these bacteria have now established themselves and even if you remove the film by the removing the water, some of the film still sticks to the side of the aquarium and you don't actually effectively remove all of it and within hours the film is back.

The trick is to place an airstone that produces bubbles under a piece of the glass cover. Bubbles then form under the microfilm and when they pop the microfilm ends up on the glass cover, which you can then wipe clean regularly. In this way you can eventually eliminate this oily film.

The film is not negative to the fishes though and nothing to majorly worry about.

Kind regards,

Dirk

 

Thanks Guys, I did recently switch off the airstone in the tank, thats why I only recognised it now

 

Does this give of the same reflection and normal oil on water like a ranbow of colours because a friend of mine that started up a tank recently had that problem and when I got there the fish were swimming underheath it gasping for air? the only way I could remove it was with a paper towel, had to run it over the serface of the water a few times and then did a 50% water change because he lost 3 fish. could it be the same stuff or is it that he might of worked with his hands in the tank while they had oil on?

 

Yes Gareth,

it does give the same reflection as "normal oil" (whatever that may mean? car oil, hand creme, cooking oil?). Such a film can definitely cut off oxygen entry into the water that will cause the fish to gasp for air. I doubt very much if it is the oil he may have had on his hands because hand creme is not only oil, but also an emulsifier, and this does not actually tend to form the films.

If you see these sorts of oily layers on tanks, you should aerate to get rid of the film and to introduce oxygen into the water!

Kind regards,

Dirk

 

I've only ever had this problem when I did not have enough surface movement. You don't need major splashing and waves - you just need to break the surface a little bit. And I've found that normally if my stems grow too tall then that restricts flow and I get this problem. Or when my filters are clogged and flow rate is reduced.