Fish are an excellent source of high quality easily digestible protien. They provide trace minerals such as magnesium, phosphorus, iron and copper as well as the following doses of vitamins in an average serving: 10% of thiamin, 15% riboflavin and 50% niacin + some B's. A serving of fatty fish such salmon, mackerel and sardine will supply about 10% of the daily allowance of Vitamin D along with high levels of poly-unsaturated fatty acids, especially Omega-3 fatty acids.

    And then there's the down side: As previously mentioned, absorbed toxins are usually stored in the fat (this is the bodys' way of trapping them and protecting the organs). In the case of fish, they absorb all of the pollutants which happen to be in the water. The fatty fish are more likely to contain dangerous chemicals. In Particular, species that are larger, longer lived, or are predatory absorb much larger quantities of toxins for obvious reasons.

    The compunds in question are: Dioxins, Methylmercury, Pcb's, DDT, and PBDE's . On fish farms, crowded conditions can conduce to exposure of a wide rage of agrichemicals designed as disinfectants and to kill bacteria in excrement laden water; herbicides to prevent the overgrowth of vegetation in ponds; vaccines to fight certain diseases; and drugs - usually combined in the feed - to treat diseases and parasites as well as spawning and production hormones.

     In nature, salt and fresh water species such as Tuna, Swordfish and Bass are known to contain high levels of mercury. Best bet : Smaller nonpredatory fish such as Tilapia or Trout raised on.... you guessed it, organic fish farms or from a known uncontaminated water source.