[james_r_edwards34]

I have been feeding my fish raw shrimp purchased from the "fresh" fish section at Wal-mart (I know I should not be shopping at Wal-mart any way but that is not the issue). There is a sign that stated "May contain sulfites". Are sulfites dangerous to my fish? Do they promote parasitic activity/life forms? I have not been able to find this topic anywhere. Any help out there is greatly appreciated. Lee I thought I read you are a chemist by education, what are your thoughts??

James

[leebca]

James,

Sulfites are chemically: SO3 (3 is subscript). It is an negatively charge ion with a negative 2 charge attributed to it.

One of its uses is as a preservative because it retards the oxidation of foods. That is, it is added to cut vegetables and things like cut apples which would brown (oxidize) when exposed to air but when treated with sulfite, this browning is retarded or prevented for a time.

The small quantities used on human foods (and included in many wines) has been known to cause humans some issues, especially when the human has been sensitized (allergy) to this and similar compounds.

The small quantity in human food however would be more significant to a small fish. Should our fish eat anti-oxidants? They should. They find them in their natural foods. Should we be adding sulfite to their food? I don't think we should. Should we feed foods with an unknown quantity of these additives? Definitely not. Natural foods have the balance the marine fish needs. Those we add, such as Vitamin C, are suitable and enough.

My suggestion would be to find another fish/shrimp source, one without preservatives or additives. In the meantime, a thorough rinse in clean saltwater and then clean freshwater should be good enough.