Copper

yea true got zink and other alkaliads that can be highly toxic

 

LOL , depending on what "year" of penny you use older' pennys of course contain more copper than say 1990's up .

Reason>
As we all know INflation !, ya cant make penny's more expensive to manufacture (components/metals only i'm not adding labor or such ), than the cost of a penny it's self .

So they make the "core" of the penny' out of other components, such as other less precious metals ie. tin, etc.


I would say though you worry way to much' of course it don't belong in your tank' the salt will most asuridly start the process of taking that penny back to its natural state , and small particles will most likely enter the water column.

But i wouldint get to bent out of shape about it.

Remidy's >

1, catch the little "Ba^&!*D" that thrue the penny in the tank and show him your "grow out tank" / or main display (both will work well) in the back room and show him first hand how diverse your most beloved world looks like head first' .( caution donot let parents of little "SH*!" see you do this ) LOL.

2, If caught by significant or other ( act stupid ) the Poor child was about to drown ' i think he was looking for his penny' in the tank.
Thank god i was here to pull him out in the nick of time before my "sohol tang" whipped his AZZ.
( you might explain to him in a fainted whisper with some eye twitch , what going postal is )in private of course..lol

CAUTION !! though when holding said "culprut' by the ankles (showing him your diverse/prized collection)
I think it's still "human" , meaning it's a "mamel" and mamels do require air to live' ! .

LOL ,

 

LOL. Karma for making me almost spray coffee.