While I was decorating my Oscar tank which by the way is probably more difficult then decorating any other fishs' tank I added some medium size rocks from the garden. They looked great with my fake plants in between so the O's don't destroy them but It has been about a week and it looks like they are rusting. I am assuming that there is Iron in the rock but will this harm my oscars or have any adverse affects??? Thanks - Jon

no, this is not going to cause any harm to your fish, it might just discolour your water slightly

got any pics of the setup you have?

a high iron content in your rocks should have no adverse affect on your oscars however you might consider removing them form your tank from a asthetic point of view.