The answer is no. Throughout the world you may find many different water environments which may all require different solutions. The three main water types are salt, fresh and brackish. Zinc and aluminum anodes protect very well in salt and brackish where magnesium anodes protect best in fresh water. Whenever possible, measure electrolytic corrosion around your boat by using corrosion test meter. This will quickly indicate if your anodes are providing adequate protection.

A special note on magnesium anodes for fresh water.

Essentially, fresh water is much less conductive environment than salt water, therefore magnesium anodes are you best choice as they are much more active (less noble) than zinc or aluminum anodes. The result is increased efficiency thus superior protection for your underwater metal components.

NOTE: It is not recommended to use magnesium anodes in salt or brackish water. The result may be an accelerated corrosion rate, which may damage the metal parts of your boat and leave you with no anode protection in a short period of time.