I believe the fear of adding rocks from a pond or stream is unfounded. If something that awful was living in it, id think you would know it.
marine keepers add rock direct from the ocean constantly, and with very few negative side affects. There are a lot of positives however... this quote about sums it up
trying to have a marine tank without adding live rock (rock from the ocean with living things on it) is like trying to garden without earth worms, soil bacteria, and fungi
(Nick Dakin, Marine Aquarium)
I find it hard to believe that there are so many "nasties" out there that will kill things in your tank. We already know many bacteria go through the air and establish themselves in your tank, would this not be how they spread to an isolated pond? Also many of us seem to fear bacteria and try to pretend were stopping them from entering our aquariums. Fish themselves carry bacteria of numerous types on their skin, as well as live plants, inverts, and anything else you add from an established tank.
This quote also seems relevant
In my experience, it is more likely parasties will enter the aquarium with their hosts, rather via other sources
(John H Tullock, Reef Aquariums)
Most likely the ponds temperature, and Ph are likely quite different from your own tank, and has the potential to kill most everything on the rocks on its own. If anything did survive, it would most likely be spores of some type of algae or plant, nothing deadly to fish or other inhabitants.
Even though the vast majority of fish keepers likely use only rock found at a pet store, or bleach or boil their rocks, there has never been a case, to my knowledge, of someone putting rock from a stream or river directly into their tank and it causing major problems. Possibly some experimentation is due from a few of us to see what happens. In my opinion, the worst that could happen is the addition of rock covered in decaying and dying life. Most likely would result in an ammonia spike which
might cause problems. Bleaching, nor boiling would do much for this condition, likely scrubbing or allowing the piece to cure in a seperate tub of water would be the only means to prevent this.
As far as PVC and ABS is concerned, there have been thousands (likely hundreds of thousands) of aquarium keepers that have used either plastic in their tank without first taking precautionary measures. Id say the vast majority of hobbyists do not take any precautionary measures, and as of yet, I have not heard of anyone having a problem.
I have numerous books that talk about using PVC and ABS and they all recommend just flushing the pipes with freshwater. None give any advice that there will be possible contamination of the piping, and they all seem to agree there is only dirt and dust to contend with.
Sorry had to put some humor in. But I do appreciate everyone opinion.
