!R My future fry in danger?

[Red Tailed Wonder]

so im avin some work done on the house... its very dusty obviously!
because its dusty i covered it with this tea towel...
my stupid brother knocked it in and now theres oily stuff on the surface, what shall i do? leave it , remove it?????
Help
:help:

 

[TheZoo]

water change?

 

[Jericho]

Yep water change and skim the top of the tank since oil floats. Get as much out as you can...