# White/clear slime on top of fish bowls?



## Jrf456

This has been happening for a while now.. It has never affected the fish, so I just don't know what it is. I change their water 100% every 5 days. By the third day, some of their bowls get this gross looking clear/white slime on top of the bowl. 

None of their bowls are covered, could this be why?

Is it harmful to the fish?

What should I do to stop this?

Any help would be appreciated.

Thanks!


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## Jrf456

Please someone help.. I'm really worried.
Why does it not look like it hurts/affects the fish? They flutter around and make bubble nests like usual.


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## Indyfishy

I'm pretty sure its just a natural thing that the fish create, all my bettas have it too =/ But it goes away when I turn the filter on in my filtered tanks.


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## Jrf456

Ohh okay, phew. It can't harm the fish though right? I mean I do 100% changes every 5 days, so will this be okay? Their tanks aren't filtered.


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## BETTA DET

How big is their bowl?


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## Jrf456

They all have varied 1g-2g bowls.


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## Indyfishy

No it doesn't harm them, its just their natural fish slime haha. In a 1 gallon bowl you should atleast one or two 50% and one 100% change every week. For the 2 gallon one 100% every five days is fine =)


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## DarkMoon17

It's just protein scum, nothing to worry about. Increased water changes would cut down on it if you don't have a filter. I do think it probably isn't great for bettas since they breath at the surface... but I don't know about that.


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## Abby

sounds like bio film.
* What is it?*

*Bio-film* (biofilm) is a thin film on the surface of aquarium water, caused by the build up of protein from organic waste material. It is the structure bacteria build to support themselves growing on the surface where they get access to oxygen and the material. 
* What does it look like?*

It can be spotted by looking at the surface at an angle to a light source and you may see reflected an oil like rainbow effect. It can also be directly seen by breaking up the surface of the water with a finger or stick to make bubbles. If bubbles form and last for more than a few seconds then you've got a bio-film. 
* Is it dangerous?*

In certain circumstances (high bioload) it can reduce the level of oxygen to the rest of the tank. It can also stop CO2 getting released from the water so CO2 levels rise and so may cause asphyxiation to the animals in the tank including the nitrifying bacteria in a filter. 
* Causes*



It can be caused in a new aquarium where the gravel release their organic debris and it settles on the surface.
It can be caused by a male Betta, Paradise or Gourami fish when he constructs his bubble nest. He uses his own mucus to form the bubbles.
Tiny uneaten food particles or decaying plant may rise and gather at the surface.
Add too much bottled bacteria may cause this.
Unfiltered tanks or tanks with very little surface movement are more prone to this than well filtered tanks.
 * Removing it*

Ensure an adequate water flow at the surface or provide aeration to break up the water surface. It will soon dissipate. In the immediate instance a fishnet can be used to take the film off the surface of the water.


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