Go with CVS Algal-900 DHA. The body needs EPA and DHA omega 3. Your body can reduce the DHA (long chain) to EPA (medium chain) pretty well. It's tougher to go from EPA to DHA, however. Krill has both EPA and DHA. But the Algal doesn't have the fishy smell. Alga is the only plant source of DHA (the brain needs DHA). Plant sources of omega 3 such as that from Flax is short-chain ALA. The body doesn't use ALA.
BTW next time you go to the grocery store look at the liquid cooking oils that say "Omega 3 ALA" ALA will be in very small print. The consumer is being duped.
Would I be putting a grain-feed cow on a fad diet if I took it out of the feedlot and put it on pasture eating the grass nature intended?