I would like to add a sand container to provide a sleeping spot for my wrasse ... the tank is barebottom but I have heard of tanks setup with containers of sand for wrasses to hide in ... I don't love the concept of a Tupperware container in my tank said:
There's a company that makes artificial aquarium rock out of a ceramic material. I can't remember the name now, but I'm pretty sure they were at MACNA last year (2013). I also seem to remember they had a rock that was open, kind of like a bowl, that someone was using for that exact purpose. I'll see if I can find out the name of the company if someone on here doesn't reply with it first. They also make rocks with holes in them for frag plugs, and the plugs to go in them, so you could have a frag rack that looked like a rock as apposed to the usual egg crate.
