I was reading another topic in the trop. fish forum, and something was mentioned about which substrate is best for cory catfish.

Are large, mostly smooth river rocks OK? (That's what I have, and I'm planning on getting some cories in the future.) Which substrates are bad for keeping cories?

Smooth river rocks are great. What you need to watch out for with cories is sharp edges, like coarse gravel. It can wear down their barbels which they need to find food.

OK! Thank you, good to know!

I was told that colored gravel can be bad for cories. When the color coating wears off the aggregate limestone it can leach into the water and turn it too alkaline. Apparently a lot of cories can't tolerate that very well.

Oh, I see. Also an interesting factoid! I got rid of all my colored gravel back during the winter.

Out of curiosity, would barebottom be ok? With a few places to hide of course.

I'm not sure on the barebottom idea. They like to root around in the substrate for food. My biggest concern would be if they do ok seeing their reflections in the bottom of the tank, since they can be a little skittish at times. But maybe it will make them think they are in a larger group.