My wife and I currently purchased a 46 gallon bow front and are thinking of a theme we want. However we are both stumped on weather or not a decoration might be toxic or lethal to the fish. We are looking to a length of metal chain similar to this one found at and also a piece of standard chain link fence. My question is would these items chemically harm the fish or alter the water in anyway? Thank you all in advance for your opinions and knowledge on the subject.