While Playing LVL4 WRLD1
First, enter the water, and keep swimming until
you see a star coin, on the top left hand side of the screen, with a pipe below it and a fish swimming right next to it. Jump over the fish,
and grab the star coin. Next, keep swimming, and hit ! blocks, until you get ice mario. Then, when you find the pipes with bubbles coming out of them, they will block your way from getting certain star coins, so do the following. For the star coin which is surrounded by a puffer fish on the bottom left hand side of the screen, throw ice at the puffer fish when it's above the pipe, and it will slowly sink and block the pipe, allowing you to retrieve the star coin. For the coin which is between two pipes at the top of the screen(this is after you keep swimming) wait for a school of fish to come when you get there. Dodge them and wait until they're completely gone. Swim forward and you will see a puffer fish. Throw ice at it, it will die and tumble down the slope. Keep throwing ice at it until it rises and reaches the pipes and retrieve the star coin.
Get another ice mario if you lose it.