Side-swimming. Jade Baldy is a marine fish that is a laterally flat fish with a laterally flat and oval shaped body. According to the biology and behavior of jade bald fish, they usually swim sideways. Side swimming is when a fish swims in the water with its body in a sideways position, swinging its caudal fin sideways to propel itself. This type of swimming allows the fish to be more flexible and adapt to currents and water conditions at different depths.