Thread:Jens Ingels/@comment-8949714-20130430123401/@comment-3271569-20130501140923

109.166.142.119 wrote: try to breed like this : ?/X + (?/)Y(/?) For Petroleum : ?/ Sea + Dark So breed Mud/Waterfall/Cloud/Coral/Poo/Pirate with Dark :D.

P.S. The higher the levels are, the better !

Good, this is indeed the correct formule. You could find the possbile conbination in the breeding tab on the available section listed on most dragon pages.