Water Breathing Potion

To make a water breathing Potion (3:00), you first need to make an awkward potion

after the awkward potion is finished put a pufferfish in the top slot and wait for the water breathing potion to finish

For a longer lasting effect (8:00) put a piece of redstone in the top slot and the water breathing potion in the bottom slot

If you want to make a splash Potion out of it you simply put a piece of gunpowder in the top slot

And if the splash potion is not enough for you and you want to make a lingering potion from it, then you just put a bottle of dragon´s breath in the top slot and the splash potion in the bottom slot