The exhibition is in a fishtank - has anyone had any experience
of harm to fish through metals or polishing compounds etc.
Some materials are fine with fish, others are not. Stay away from
copper, brass, bronze, etc. Sterling silver is probably OK, so long
as it was soldered with hard solder or better. The copper is what's
toxic, silver itself is a decent antibacterial (the old french foreign
legion issued canteens to the troops with silver plated interiors,
since it kept the water therein from going bad and growing things).
but it seems relatively inert insofar as higher organisms. If the
tank in question has invertibrates, then even this might be a
problem, but for usual fresh water fish, you'll be fine. As to the
problem with copper, this an be also the case with some stones, too,
like malechite and turqoise. These copper minerals shouldn't go in
gold plating will help, but don't use a nickel or copper underplate.
that means the gold plating won't be all that permanent if on silver,
but it will last well enough for your show.
If this is a salt water tank, though, then all bets are off. Salt
water fish are often FAR more sensative to contaminants, and the salt
water is much more corosive too.
As to the polishing compounds, by all means clean the jewelery
properly. Ordinary silica based compounds like tripoli and white
diamond are from ancient sea floors, and aren't likely to harm fish
either, though the wax and grease binders might be different. But
polishing compounds on your work will be mixed with finely divided
metal, and this clearly is not a good thing. So be sure your work is
If the owners of the tank wish to be cautious, I'd recommend adding
to the filter, some of the ammonia removing chips, or the mix of
those with activated carbon. The ammonia removing chips are
zeolites, which are capable of removing traces of heavy metals,
though they're not all that great at it. Still, it's good
insurance. (carbon filters and normal acquarium filters won't take
such things out.)
And get a liability release, so that if the fish all croak, you're
not stuck with the tab. Some fish loss tends to be a routine, if
occasional, normal feature of keeping community tanks. It just
happens sometimes, even without jewelery in the tank.