When we first built our main pond and stocked it, the wife set up an aquarium in our living room. We put I think 4 short pipes about the same size as the one in your picture in the bottom and put a dozen or so FHM in. It was funny to watch them dart from pipe to pipe, the more dominant ones chasing out the others positioning and creating their "pecking order".
We did not keep them long enough for them to spawn in the aquarium but we did see some pre spawning behavior in the pipes with dominant males staking out their territories.
