[Michael]

I have only seen sand in saltwater tanks. I can't see why you couldn't use sand in a freshwater tank, though. Just be careful because a lot of the aquarium sand pet stores sell is treated with bacteria meant for saltwater tanks. I'm not sure how it would affect a freshwater setup.

 

[Michael]

Hi Libby, by "rays" do you mean sting rays? Are there freshwater sting rays?

Sometimes you have to worry about the roughness or size if you have specific bottom dwellers or feeders. For example rays need sand or they scratch themselves when burying. Otherwise i always use gravel becasue fish waste and stuff doesn't sit on top of it like it does with sand. A small sized gravel in a natural brown or tan color usually does the job.

Libby