Vegan diets tend to have a worse omega-6/omega-3 ratio than omnivore diets. Something many vegans don't realize.
The site http://www.veganhealth.org/articles/omega3 has good info and recommendations for getting enough omega-3 as a vegan. He recommends taking a DHA supplement from algae. Apparently EPA isn't so important, since vegans can make EPA using ALA, which is found in plant foods.
I don't know if the omega-6/omega-3 ratio is generally better for lacto-ovo vegetarians than for vegans.