New Super Mario Bros.: 4-3

It's another water level. Take the pipe down to the water, where the level is an automatic sidescroller. This level is crawling with Unagi, some above, some below, and some in the rocks. The first Star Coin is under a ledge. There are Red Coins in the water. The second Star Coin is between two Unagi in rocks, so time your swimming to avoid them. There will be an orange ? Switch that stops the currents near some pipes. Take the last green pipe down and avoid two Unagi in rocks, go left, then down, to reach the third Star Coin. Go back up and you'll find four Unagi in rocks near the pipe to the flag. There is a Goomba on the staircase.