Everyone knows that fish use their fins to swim. But you'll learn a lot more than that by taking a closer look. The bass caudal (tail) fin, for example, is broad and slightly indented with relatively equal sized lobes. That design is ideal for short rapid bursts of speed and a great asset when feeding. A 20-inch bass can accelerate to almost 12-miles-per-hour. That's about five times faster than the average crankbait retrieval speed.