Question about using seashells and rocks...

[ryorgason]

Is it safe to use shells and rocks found at the beach in my aquarium? What is the best way to clean them and make sure they won't leach salt or anything dangerous? I have cories and would like a pleco or two eventually, so don't want salt in my tanks.

 

[An t-iasg]

There is no safe way to incorporate shells and rocks from the beach into a freshwater tank. They will always be leaching minerals into your water, which will raise your pH. Some people do use crushed coral (probably similar to your beach shells/stones) in a FW tank specifically to raise the pH, but they are usually raising the pH or keeping stable a higher pH for fish like African cichlids.

Keep in mind that the stones and shells will dissolve over time as they leach minerals into the water. If you like these shells and stones, then don't put them in your tank, or eventually you won't have them anymore.

 

[newfound77951]

I agree that beach shells should not be put into a FW tank. Rocks, on the other hand, it depends on what kind of rock it is. I have many rocks I found on the beach in my tanks. Any inert type of rock (granite, slate, shale, sandstone, basalt) is fine in a freshwater tank. Limestone, marble, dolomite, coral skeletons are not. If you are not sure what kind of rock you have, post a pic of it and we'll see if someone here can ID them. The rounded, dark gray or black "beach rocks" you commonly see are usually basalt and are fine in tanks, I have several in my 10 planted tank right now. But be sure you know what you have!

If you find a suitable rock from anywhere, you can boil the rock to kill most critters or spores that you don't want in your tank. Alternatively you can bake the rocks in the oven, I've done 200F for an hour. It doesn't have to be super hot, just hot enough to kill anything living.