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Is Zinc ok to have in a fish tank?

(Edited to facilitate searches later on Calla)

"I am who I am, and who I am is who I want to be."
-Kasey Carter

Are you talking about the a product called "Zink", elemental zinc (Zn), something in the aquarium that contains zinc (such as a decoration), or zinc levels in your water?

Joe Potato

the drift wood in the tank is attached to a peace of slate using L-brackets. they are zinc.

(sorry about spelling zinc rong, I stink at spelling.)

"I am who I am, and who I am is who I want to be."
-Kasey Carter

I've read that water containing zinc ions is toxic, but I'm not sure if just having the zinc brackets in there is enough to cause a significant amount of free zinc ions. Did the driftwood come mounted this way, and if it did was it made specifically for aquariums? I think some zinc alloys are safe to use in aquariums, but I'm not sure if pure zinc is.

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I'm not your neighbor, you Bakersfield trash.

Most commonly encountered, plant-necessitated transition metals are harmless in their chelated forms. I assume (and hope) that zinc is no exception

I'd play safe and swap the mounting brackets for inert plastic.

Zinc plating is used on iron and steel for a very good reason. It has a higher electropotentiol in chemical reactions than iron, and so if the plating surface is scratched, it acts as a 'sacrificial anode' and corrodes instead of the underlying structural iron or steel. Which means that in an aquarium, if the brackets on your decoration are in fact zinc plated instead of a zinc alloy, you could be storing up some trouble for yourself.

Just took a look here and scrolled down to the section on zinc toxicity. It is an important trace element for life, but only if taken in the form of certain zinc compounds that occur naturally in the food chain. Free ionic zinc in solution is highly toxic to invertebrates (the page mentions that only a micromolar solution is required to kill Daphnia) and free zinc ions in solution are probably not going to be good for fishes even in modest concentrations.

I'd discard the mounting brackets and replace them to be on the safe side.


Panda Catfish fan and keeper/breeder since Christmas 2002

If you're working with something containing galvanized steel, then you have more to think about than just the zinc, as the oxides formed by steel develop so abruptly (and disperse) that it’ll probably be those that do the fish in, not the zinc. God, I hate electrochem.

Its been in the tank for about a year, and no fish have died, so I guess its ok.


"I am who I am, and who I am is who I want to be."
-Kasey Carter

The tiny fraction from the Zinc is not going to be an issue if you do normal water changes which is a good habit anyways.
I've use similar materials without issues for years and a lot more zinc metal than the brackets you have.

Sure, high levels are toxic, but unless you test, and given that plants absorb a lot, and are exported as cuttings, you are a long way off before it's ever going to be a problem.

Regards,
Tom Barr