@eisly asked what kind of patterns would be drawn on these fellows, and I got a bit carried away! Popular patterns are radial or spiral, involving glued on items such as crystals, rocks, or shells from smaller discbacks, as well as staining the shell with pigments! If decor is used, it’s more common to carve out a divot and glue it inside, so that it is flush with the shell and has less chance of being knocked off when they trundle around.
The other images are a Karragul child holding their disgruntled pet (right), and a temporary holding pen (bottom). Discbacks are pretty bad at moving over anything other than a flat surface, especially when not buoyed up by water, so even a short barrier is enough to contain them.