Fish safe wood finish??

[enlightened]

It was suggested i re-post my question in this forum.  I belong to a woodworking group and one of our members posted the following.

I have made a water wheel out of wood,  for my small Gold Fish pond in my
  yard. the kind with the little buckets all the way around and the wheel turns and
  dumps water into the pond.
 
  Question--- What kind of Stain, Sealer, and Caulking, can I use that is   
  Non Toxic to my fish? Any help will be certainly appreciated thanks

I have come here seeking your guidance for him (as well as other woodworkers) regarding this question.  I hope you won't mind the intrusion.

Thank you in advance.

Mike

[Rocmon]

I don't know of any finishing product that would be safe for fish. Paint product generally have anti-fungals, and oils I'd be afraid of. Constructing of redwood or similar wood may help. I would expect it should last awhile unfinished and look natural that way... Sorry, I'm no help.

[kennef]

Marine spar Varnish, once cured is completely waterproof and inert. i have used it in wet applications before and its been fine

[enlightened]

Thanks for the responses so far.  they are appreciated.