oil

Question
how would you remove oil from fish pond spilt in error from motorbike. s stroke oil. floating on top.  

Answer
Use paper towels and rags to try to soak some off of the surface, as much as you can.  Skim the water off the top.  Do a partial water change.  Put a mesh bag of fresh activated carbon in the filter to help chemically remove more oil from the water.  I hope it was just a little bit.  If there's a lot, there may not be good air exchange at the surface so extra aeration may be needed to prevent suffocation of any aquatic animals.  Good luck.

Robyn
fishpondinfo.com