comments:
Everyone's kinda being a downer about this but if you want to add them I'll tell ya how to test it. Get a bucket of aquarium water and an airstone, seperate from your main tank. Before adding the rocks, do the vinegar test. If any fail, they are immediately out. Then use acetone (pure, not the nail polish remover with additives) to test for coatings; start rubbing them down or doing a quick soak then using an old rag to wipe. If any of them become gummy or start shedding dye, they are out too. After this, you will need a heavy metal testing kit, the strips for tap water work just fine for this. Rinse your rocks thoroughly, then add them to the bucket and wait about a week. Treat the bucket just like your aquarium, except top off the water instead of full on changes, and test daily for heavy metals. If none have leeched beyond this point, it's most likely safe. Dyes may also show up at this point in which case you'll need to toss the whole batch. I'll also throw out there that most tumbled polished rocks are forms of agate, quartz, or jasper, which are typically fine in an aquarium. But to be extra safe, follow these steps, and happy rock hunting! ETA: Here's an amazon link to some dye free agate, it isn't quite as colorful but I think they're pretty! Dye free agate is what you'll wanna search for.