I always take lots of pics! Be patient, I still have to wait for my acrylic lids to arrive so I can replace my old glass ones and use the old glass ones to make a tank. Reduce, re-use, recycle!
Yeah, I was thinking flat rocks too, perhaps siliconed into place? Making a background seems like a bit of a pain in the rear end but if I can track down some epoxy resin then I'd be keen to give it a go.
How else could I secure the rocks?