My breeding tanks are completely bare.....Well not quite bare....I do have a heater and powerhead in there, but that's it....The pair spawns freely on the bottom floor of the tank....
I have about a quarter inch of gravel, some driftwood with java fern tied to it, some jave moss sitting in the corner and a small sword in another corner. I have 3 or 4 terracotta pots and an antique looking jug. They always spawn in the jug.