Koi pond in between decks. Pergola and decking are redwood. Concrete pillars under the steps for support. There are ample space in between the supporting pillars for koi fish to swim by, provides cover from sunlight and possible predators. Koi pond filtration is located under the wood deck, hidden from sight. The water fall is also a biological filtration (bakki shower). Pond water volume is 5500 gallon. Artificial grass and draught resistant plants were used in this yard.