Need Help... What's This?

[slakey]

Hey all,

I have got this weird patchy substances on the waters surface in my new tank, and well I'd like to know what it is, and how to get rid of it.

It looks as though petrol has been spilled into the water.
I'm guessing it might just be toxins.

Any help would be grateful.

 

[WILDER]

Soak it up with kitchen paper just float it on top of the tank.
Is the subatance greasy.
How are the fish acting.