This is a variation of the all-round game where you can choose the number of reels to include. Using the multiplier of the bonus game, there is no real reason to play a reel less than the full 5 5. The symbol on the left continuous reel will trigger the prize regardless of its position. You will trigger this by hitting 3 gold coins on the reel.
The classic version allows you to choose one of the five koi - this will let you know where the slot's title comes from!