Stacking Objects

I am trying to stack a moonwell and then a fountain (very small) over top to make it look like the moonwell is geysering. I was then going to add fish to the moonwell. I'm having trouble getting the moonwell and fountain to 'stack'.

If both are units, one of them must be a unit (not a building) and with flying (or movement = none).

If at least one of them is a doodad, you can remove its pathing texture (set to NONE) and put it over the other.