The nutritional composition was studied of green seaweeds ( Chaetomorpha linum, Rhizoclonium riparium, Ulva intestinalis, U. lactuca, U. prolifera) grown in fish pond aquaculture systems. Moreover, anti-inflammatory activities were measured. The effects of bioaccessibility on this property were assessed. There were qualitative differences in the lipid composition, since fatty acid profiles varied among seaweed species. Whereas U. lactuca and U. intestinalis fatty acid profiles were very similar, all other profiles differed significantly. U. prolifera was very rich in ω6 PUFA, while R. riparium was richer in ω3 PUFA. Concerning the ω3/ω6 ratio, the highest value was found for C. linum. The anti-inflammatory activity was higher for U. prolifera and C. linum with high cyclooxygenase-2 activity inhibition (ranging between 18 and 27 %) upon incubation of 100 μg/mL of these green seaweed extracts. Though the compounds causing this effect were not bioaccessible, U. prolifera seems to be a potential source of bioactive compounds.