Figure 4.

Front view of the aquarium (45 L) divided in half with a watertight, clear divider (gray midline), and a removable opaque barrier (black midline). There is a small male fish (left compartment) and the large male fish (~4 × larger in the right compartment). The half terra cotta pot (red curved line) was cut so that both fish “shared” the same shelter, although they were not aware of each other’s presence. This “shared” shelter was hemisected by both center dividers. A layer of gravel covered the bottom of the tank.