Cod (Oilfish)

Scenario: You want to prepare a candle night dinner for you sweetheart tonight. He/She wants you to make him/her cod fish as a main dish. You then go to Park n Shop and find several packages of fishes at the fridge. Some fishes look like cod.
You take it up, look at the label - it states 'Cod (Oilfish)'.
'Who on earth would know that Cod has two names?' You grumble. After all what you need is cod, so the package tells you that the stuff inside is cod, you now pick up one pack and go ahead to the cashier.
You cook the Cod (Oilfish).
You serve yourself and your honey the Cod (Oilfish).
You digest the Cod (Oilfish).
You and your honey have diarrhoea... the 'Cod' and 'fish' seems to be digested, but not the 'Oil'....
The situation continues for several days.
You get healed, you want to complain Park n Shop, then they reply you the fishes have no problem, it is your own stupidity causes you the sickness. It is YOU who did not study well in your biology class then YOU lost a chance to be a researcher or professor in University to study about the difference between Ruvettus pretiosus and Gadus.

And then Mr. Li tells you, "this is your bloody own fault, not us... I tell you what, I am going to donate a big buck to Biology department of the University of Hong Kong and I am sure the Vice Chancellor dares not to not putting my big name on that flashy building..."