Galvanized steel fish pond

[Jim T]

Is it safe for fish to use galvanized steel trough for a fish pond?

[Fish Folk]

I would recommend against it. Zinc build up can kill fish. Here’s an article on that.

I recommend a food-grade feeding stock tank from Tractor Supply. I use 40 gallon, but most serious tub folks buy larger than that…

[nabokovfan87]

I do believe it depends on the materials. I seem to recall Rachel O'Leary had a few metal ponds and I do not know if they were plants only, but I will attach her video below on tubs.  You can toss in a liner too just to do it that way. 
 

If you haven't seen Zenzo's pond, I highly recommend checking that out as well!

Edited June 30, 2023 by nabokovfan87

[TJOBrien]

I looked at this article and many others, combined with my background knowledge of metallurgy, there doesn't seem to be any evidence that zinc is contaminating water. 

As I understand, the zinc oxide that forms on the surface prevents it from coming off. And zinc oxide is inert, there is a lot of fear around heavy metals in welding as well, it has been determined over and over again that it is at most an irritant as it's particles are large enough to pass through or be filtered out of air and water. 

So as long as you change your water occasionally and clean your filters, there should not be any build up of zinc.

Same idea in welding, wearing a mask with particulate filter is all that is normally used, even if you don't you'll be fine. You may get a bad headache and cough for a few days that feels like the flu, but no long term affects have been found in humans or animals that I know of. 

The EPA is always looking for things to ban, if they still have no problems with it after it's been applied to metal, I don't think it is a problem. 

Heat is a big problem with a metal tank above ground. Metal stock tanks can get really hot. 

Buying a used stock tank is always better as the oils will be removed and the galvanizing will have formed a thick oxide layer from being exposed to weather for a while.