Given my extremley limited food budget, I was considering using fish (basically non-caned sardines and mullet), as my main source of protein. Those are the cheapest meats I can get, and as far as I know they are low in the food chain so they have little chance to store much contaminants (compared to bigger predatory fish like tuna). Plus they are high in omega 3, and by far cheaper than wild salmon. My real concern is with protein allergies, would it really be a problem under this circumstances (eating large amounts of fish on a daily basis)?