Thanks.
I'm not too sure if I should be too worried about a cover. He is not being bothered, and my tank is acrylic with euro-bracing on most of the top, except for 2-15"X7" openings. There is a canopy and he seems to be doing very well. I have some fish netting I might cut and use for those openings though.
He is building his burrow at a very fast rate and using some rocks I didn't think he could move.
