A recent study published in Archives of Pediatrics & Adolescent Medicine links prenatal mercury exposure with a greater risk of ADHD-related behaviors. The study also finds that maternal fish consumption during pregnancy can help reduce the risk of ADHD-related behaviors in children. This duality is possible because many types of fish have low levels of mercury, so it is possible for a pregnant woman to eat nutritionally beneficial fish without being exposed too much mercury. 
Fish has always been the best source for the animal-based omega-3 fats EPA and DHA, but as levels of pollution have increased, this nutritional powerhouse has become less and less viable as a primary source of healthful fats.
That said, by choosing wisely, the benefits of a diet high in fish can still outweigh the risks. Let’s examine a few topics that will help you make better choices.
Choose Wild not Farmed
In this case farm-to-table is not a good thing. Naturally, fish swimming in the wild get more exercise, and this alone make wild fish healthier than their incarcerated counterparts. As explained by Tony Farrell with the University of British Columbia Zoology department, fish kept in constrained environments become the aquatic version of "couch potatoes," with similar health consequences as humans face when we don't exercise enough. 
Wild salmon swim around in the wild, eating what nature programmed them to eat. Therefore, their nutritional profile is more complete, with micronutrients, fats, minerals, vitamins, and antioxidants. Farmed salmon, on the other hand, are fed an artificial diet consisting of grain products like corn and soy (most of which is genetically modified), along with chicken- and feather meal, artificial coloring.
Mother Nature never intended fish to eat these things, and as a consequence of this radically unnatural diet, the nutritional content of their flesh is also altered, and not for the better. Farmed salmon tastes different than wild-caught, and much of it has to do with the altered fat ratio, which is dramatically different. Farmed salmon contains far more omega-6, courtesy of their grain-based diet.
The ratio of omega-3 to omega-6 fat of wild salmon is far superior to farmed. Wild salmon typically has 600 to 1,000 percent more omega-3s compared to omega-6s. So whereas farmed salmon has a 1 to 1 ratio of omega-3s and omega-6s — again due to its "junk food" diet — the ratio for wild sockeye salmon is between 6 and 9 to 1. This is important, because if you're trying to improve your omega-3 to omega-6 balance, you simply will not accomplish it with farmed salmon...
According to Randy Hartnell, founder-president of Vital Choice Wild Seafood and Organics, studies have discovered that as much as 70 to 80 percent of the fish marked "wild" were actually farmed. This includes restaurants, where 90-95 percent of salmon is farmed, yet may be mis-listed on the menu as "wild." The following tips that can help you determine whether the salmon is authentically harvested Alaskan fish are:
1. Canned salmon labeled "Alaskan Salmon" is a good bet because Alaskan Salmon is not allowed to be farmed.
2. In restaurants, mislabeled salmon will typically be described as "wild" but not "wild Alaskan." This is because authentic "wild Alaskan" is easier to trace. The term "wild" is more nebulous and therefore more often misused. In many ways it is very similar to the highly abused "natural" designation.
3. Whether you're in a grocery store or a restaurant, ask the seafood clerk or waiter where the fish is from. If it's wild, they will have paid more for it, so they're likely to understand the value proposition. Since it's a selling point, they will know where it came from. If they don't have an answer for you, it's a red flag that it's farmed, or worse... The US Food and Drug Administration is moving forward with approving genetically engineered salmon to be sold, and GE foods still do not need to be labeled in the US.
4. Avoid Atlantic salmon, as all salmon labeled "Atlantic Salmon" currently comes from fish farms.
5. Sockeye salmon cannot be farmed, so if you find sockeye salmon, it's bound to be wild. You can tell sockeye salmon from other salmon by its color. It's bright red as opposed to pink. The reason for this bright red color is its high concentration of a powerful antioxidant called astaxanthin. 
So besides sockeye salmon (best) what are the best and worst fish choices based on potential mercury exposure?
The fish lowest in toxicity, and highest in healthful fats and other nutrients include wild caught Alaskan sockeye salmon, and smaller fish like sardines, anchovies and herring.
Avoid larger fish that are higher up in the food chain, as these tend to be far more contaminated with methyl mercury and other environmental toxins; tuna, halibut, walleye, sea bass and sword fish.
If you’re not certain about a particular type of fish check out this outstanding tool that can be very helpful in making better choices:
Out of necessity I have become the king of quick and nutritious meals try this one to get your animal based omega-3:
1 can sockeye salmon (drained)
Fresh guacamole (about ½ cup)
½ finely diced sweet pepper
Mix together (sea salt to taste) and serve on bed of lettuce. A side of freshly sliced pineapple of mango rounds out a great tasting and nutritious meal. Serves 2.
Fish consumption may not be the only way you and your child are being exposed to Mercury. Is it time for your 6-month check-up?
As if farmed raised salmon isn’t bad enough soon you may be eating genetically engineered salmon and you’ll never even know it!