PlanetCatfish.com

i have a cory tank with 2 guppies and 1 platy and i would like to know if i could have rocks from outside in my tank with my fish

It can be tricky determining which rocks could raise the pH in your tank. Another thing to consider is the condition of the soil and water in the area the rocks come from. What if there's pollution? It can all get complicated. If you have a background in geology and feel confident in your abilities to identify rocks, go for it. I'm not confident so I purchase the rocks from on-line stores. There are several which sell rocks just for aquaria. They'll tell you which ones will maintain the pH in your tanks.

what websites do you go to for the rocks for my tank?

Isn't Rhode Island famous for it's Granite? Maybe I've got it all wrong, but Granite is pretty much neutral and non-toxic.

Don't know about stones in general, but here's some ideas:

Definitely avoid:
Chalk-like stones (unless you want really hard water, like for African Rift-Lake Cichlids)
Soft/porous stones. These have a higher likelyhood of containing something inside them that slowly leak out.
Anything that looks like metal. For example, "fools gold" is not a good idea.
Mining-leftovers is not a good source of stone... [Quarry stone is a different story, as long as the quarry stone is good in other ways, i.e. not chalk/sandstone, it's probably fine for tanks too].
Avoid stones that discolour easily (i.e. if you break it, does it look dramatically different inside, or just "cleaner").


Good sources:
River-stones. If a stone has been washed with river water for some time, it's unlikely to release anything harmful into your tank at any rapid rate. [Obviously, if the river is also the local drainage from the city dump, chemical plant or mining industry, please look at going elsewhere...]
Same with beach-stones.

You can usually buy nice rocks/stones in the local garden center. Again, use the above guidelines for what stones are good for fish-tanks.

Always wash any stone that you want to use in the tank, preferrably with bleach and/or boil it. Make sure you rinse it well after using bleach of course.

Testing it with a bit of vineger if you're in doubt. Anything that bubbles/fizzles when a drop of vineger is dropped on it is only suitable for that Rift-lake tank, as it's containing some sort of Carbonate, whether it be calcium or otherwise.

Note: These are pretty simple guide-lines, and I take no responsibility for what happens to your fish if you follow these guidelines. If you want someone to blame, I suggest you pay for the stones in the LFS, and go back there if you think you got bad advice...

--
Mats

Close, Mats! New Hampshire. "Granite State." Pretty good from across the ocean. Rhode Island is the "Ocean State." Known for high levels of Radon gas in the ledge..... Several friends and loved ones had houses test off the charts. It's in the rocks.

That Fish Place, go to the substrate section, on-line. They have river rock, purple jasper, red jasper and a lot of quartz. Call them and they'll help. Google the name.

thanks for all of your information and help

Test the rocks with HCl (hydrochloric acid), if they get foamy/frothy don`t use them becouse then they are out of calcium wich would bring your water over pH 8
Also you can give them into clear water and make several tests

Dilute HCl is the best test, but most people dont have that laying around the house. Vinegar might not react with all rocks containing carbonates (ie mixed carbonates and lots of sand) though. Livebearers might like the higher pH actually, but the cories might not. My pH was 8 over the summer, and I dont think my bronze cories cared.

I'm certainly no expert on RI, but dosent the radon come from burried granite intrusions? If so, you would have granite under you, but no telling whats on top.

if i did have granite under me what would it look like?

sorry im not goos with rocks

Do you have a Home Depot or a Lowe's near you? The next time a parent goes, ask to go with them. I know this will freak them out. Tell them exactly why. You want to know what granite looks like and where you could find some for your fish tank that would be cheap and safe.

Ask to go to the kitchen countertop section. In the kitchen countertop section, all the latest rage is granite kitchen countertops. There is an assortment of colors, etc. Ask them where you could find some for your fish tank. Could they recommend a store? Plain and simple. That's it!(maybe they'll have free samples-Home Depot, Lowes, etc.)

Just remember, no marble, no laminates.......

OK thank you for all of your help

That doesnt actually work too well. In the countertop trade, any large grained rock tends to be called granite.

Granites, are white and black, and sometimes pink. The black countertops are usually a differnt rock. I need to find some of my links, but searching for granite, or rock types should get you some info.

Thanks for the info, Psy. You are correct. I did a little research. Here's a link to a page with the "commercial" definition and the "geological" definition of granite. Two different things completely.
http://www.findstone.com/daniel1.htm
The first part of the article describes the true differences. I don't understand the rest of the article. I'm not a geologist! I apologize for the misinformation.