In the wild they swim verticle in reed grass, and against tree stumps. If you put any verticle decoration in their tank they will do the same thing. It's thought that the cream and black stripes are supposed to simulate a camoflauge of reed grass and shadows when small. They get more spotted as they get larger and the cream turns more of a dark golden color. Or like mine it just turns almost completely black. lol. They sometimes hunt like this, but more likely that they are hiding from predators at a smaller size in the wild by swimming verticle in the reed grasses.