rocks & plant pots in tank

Is there any problems with putting a rock in the tank? Like a rock from
outside (stone) I guess it would depend on what kind of rock and I don't
know how to explain, but its just a gray rock/stone, I guess like the kind
you would find in your yard? I just wanted to put it in to hold something
down.

Also I have seen plant pots (the orange ones) ceramic I guess they are, in
tanks before I have one and was going to use it so I put it in water over
night to clean it and noticed the next morning some of the water was
orange, so I did not put it in the tank, is there special ones like made
for tanks, or is that normal for color to come off?

I like to decorate with natural rock as well (as well as brick and such).
I'm not too worried about putting natural stone in a tank, but brick and
ceramic I usually soak for a couple of weeks in a bucket of rainwater first.
Some stone will alter your ph and hardness so keep an eye on that. Be very
wary of ceramic, especially the cheap crap - some of it has really poor (and
often toxic) glaze and isn't suitable for much of anything. Scare story: a
family friend and her children became ill and were eventually diagnosed with
lead poisoning - it turned out to be coming from a ceramic juice pitcher
she picked up at a market in Mexico that was absolutely beautiful but had so
much lead in the glaze that anything acidic (like orange juice) would leech
it out

--
John D. Goulden
mostly goldies, guppies, swordtails and bettas