no, they don't need sand. barebottom makes it easier to clean, although some people keep it in the tank to make it look more natural and comfortable for the ray. but rays that feel comfotable in their tanks rarely bury themselves anyways, so feel free to keep it bare
I use sand in our breeding tanks. A friend has a bare bottom tank and I think it shows the rays' colors off more. I've also kept rays on smooth gravel. They can and will do well on just about anything.
I use sand in our breeding tanks. A friend has a bare bottom tank and I think it shows the rays' colors off more. I've also kept rays on smooth gravel. They can and will do well on just about anything.