What enables the fish to swim and maintain floating?

The ability of fish to swim and maintain floating is attributed to two primary factors: their streamlined body shape and the swim bladder.

1. Streamlined body shape: Fish have evolved a streamlined body shape that reduces drag and allows efficient movement through the water. Their bodies are typically elongated, with a smooth, rounded shape that minimizes resistance. The shape of their fins, such as the pectoral and pelvic fins, also contributes to stability and maneuverability.

2. Swim bladder: The swim bladder is a gas-filled organ found in many species of fish. It acts as a buoyancy control device, enabling fish to maintain their position in the water column without expending excessive energy. The swim bladder is located in the abdominal cavity and can be adjusted to change its volume. By controlling the amount of gas in the swim bladder, fish can regulate their buoyancy and maintain a desired depth in the water. When the swim bladder is filled with gas, the fish becomes more buoyant and can rise in the water. When the gas is released, the fish becomes less buoyant and can sink.

In addition to these two main factors, other features contribute to the swimming and floating abilities of fish. These include the presence of fins, which provide stability and control, and the lateral line system, which helps fish detect movement and changes in water pressure.