You probably shouldn't use clay directly in your tank, but you can create a clay-like look with various artificial materials.
It is true that care should be taken when combining strong currents and clay.
Here are some pictures of my clay-bottom tank (Special Kitty brand kitty litter is 100% baked ground clay).
The water was quite cloudy right after filling it with water:
murky when filling:
http://gallery.nanfa...ttling.jpg.htmlone day after that photo:
http://gallery.nanfa...+after.jpg.htmlI only had a 55-75 gallon waterfall filter on my tank. If you've got plans for a powerhead blowing onto or really close to the bottom, it might not be compatible with clay. Any really strong current right next to the clay can suspend small particles and make the water murky for a long time.
Also if the fish enjoy digging I've heard they can make a real mess with sand-y or soil-y substrates. I've never had any problems myself with my experience mixing clay and swordtails, guppies, darters, Elassoma gilberti, platies, danios, and hatchetfish, but you'll notice none of those are burrowing species of fish. Or at least, that's what I tried to tell the Elassoma gilberti, but they get pretty freaked out when you catch their friends with a net:
http://gallery.nanfa...hiding.jpg.html ha ha, burrowing, ha.... okay, it was a bad joke. XD
Hey, if you're out collecting for this tank and you see any Potamogeton richardsonii, let me know, okay? I looked for it when I lived in Cleveland but couldn't find any. Then I moved to North Carolina and now my odds of finding it are really slim, or so the range distribution maps tell me. So I'd pay for you to ship it to me if you find a few strands.
Edited by EricaWieser, 02 April 2012 - 06:18 PM.