I've got a 2.5, a 5.5 and a couple of 10s, one of which is going to be a dwarf puffer tank, and one a betta tank. For the DP, I was thinking about getting some slate cut in squares and rectangles and aqarium sealing it together into a sort of honeycomb cum southwestern cliff dwelling, and then tiling the rest of the tank floor with a javamoss lawn.