Do you think it's safe to put flagstone in a goldfish tank?

Hi,

i was wondering if it's safe to put it and build it. its a 20 gallon goldfish aquarium! a few question!

is it safe for the goldfish?

will it put to much pressure on the glass? (it's about 70 pounds)

how do i clean it fist

and will it change the PH?Do you think it's safe to put flagstone in a goldfish tank?
Hello Ddd I have taken some rocks from beside a railroad track I brushed them off under running water then I boiled them in a pot for a few minutes to get read of any harmful bacteria.

IT well not put to much pressure on the glass if you don`t put it against the glass.Even if it did change it would not change it enough to do any harm.

Goldfish are hard to keep alive,just look at all the sick goldfish on this web-site.I would get something els.Do you think it's safe to put flagstone in a goldfish tank?
Well, it depends. If the stone is all natural and hasnt been cleaned with Muriatic acid then i would say yes go for it. There is no way to tell for sure that it is acid free.