If you use the classic or deluxe version, the main bonus functions of the game are very similar, although the deluxe version is more comprehensive. You will trigger this action by hitting 3 gold coins on the reels.

The classic version allows you to choose one of the five koi carps-this will give you an idea of the source of the slot name! The five Koi have the same appearance, but with different colored backgrounds. Your first choice is to have 25 free games, each of which can see any win using the Koi Wild symbol multiplied by 2x, 3x or 5x. Although the multiplier has increased, the number of free spins available for the other four options has decreased. The minimum spin number available is 10, and the available multipliers are 10x, 15x, and 30x. As with these "choice of volatility" options, so should long-term wins.