There is no RDA yet, but sources agree that Americans do not get nearly enough omega-3, and way too much omega-6.

Doctors involved in the Workshop on the Essentiality of and Recommended Dietary Intakes for Omega-6 and Omega-3 Fatty Acids suggest "adequate intakes" of each:

omega-3: 0.65 grams (g) of EPA and DHA combined (with neither falling below 0.22 g)
omega-6: 4.44 g

Currently most people get 5 times more omega-6 than they need due to vegetable oils used in most salad dressing and cooking of restaurant foods as well as packaged food products. Use olive oil and butter where possible.

Other seafood like lobster, clams and crab also have omega-3.