Yep, because of the EFA's (Essential Fatty Acids , like Omega-3, 6 and 9). I was studing this with my mother and found that the Flax plant oils and Fish oils are no different in how they are absorbed into the body. They have the same effect, however humans take better to plant-based, organic sources rather than animal sources.
Also, you have to be careful of rancid oils. No, this isn't harmless but Fish oil and Flaxseed oil supplements, once pressed, become rancid and do not have the same effect as getting your EFA's from eating an actual salmon dish or flaxseeds. If you opt to take supplements, order from a company that processes the oils in a manner that doesn't speed up rancidity. Store-bought supplements are almost always rancid and sit on store shelves forever. Order directly from a manufacturer to get the best quality.
All in all, it's better to eat your EFA's than take them in a supplement. The natural oils are not rancid in this form.