Fish oil cholesterol
is just cholesterol, so it is bad if you eat too much of it. There probably isn't much cholesterol in fish oil anyway, it's about 1%.
But the other stuff in fish oil is what might be good for you: Plenty of unsaturated fat
. It breaks down much easier than saturated fat and decreases inflammation in your fat tissues.
The problem with fish oil (besides the taste and smell) is that it often contains many pollutants, such as mercury.
So go ahead, and eat your fish-oil, but I would use it INSTEAD of other oils, not IN ADDITION TO your other oils.