Is it possible to use a piece of driftwood you find in the lake in your goldfish tank? If so, what can you do to make it safe? Or, is this a bad idea?

You can use the driftwood in your tank if you wish. I boil the wood pieces I use - I boil them for at least 10 minutes at a rolling boil. If they are still releasing tannins, you can soak them for about 2 weeks and then boil them. Plunge them into clear water again to see if they are leaching any tannins out anymore - they will make the water orange or brown.

That said, driftwood that is decomposing in a tank can lower your pH - so you will want to keep an eye on it. You need to make sure that your water is well buffered to absorb this and prevent fluctuations.

Thanks Daryl.