Not entirely true. Fish canned with oils does tend to have some of the omega-3 leech into the oil. I personally solve that problem because I consume much of the olive oil in the can. Fish packed in water do not lose very much of the omega-3's but now you get a much fishier taste.
The olive oil really does enhance the taste profile of the sardines however so I prefer the olive oil.
I would avoid any fish packed in soybean oil.
Soybean oil not good!
Yes, beware of the soy oil variety it may turn you into a very unmanly soy-boy.
It’s the other way around. Water leaches the Omega-3s out. That whole oil and water thing. Packed in oil, the Omega-3s remain.