Fertilizer · Aquaponics
Crayfish waste as fertilizer
Crayfish are extremely dirty animals. They eat — and produce waste from — both plant matter and dead animals, since they're scavengers by nature. Because of this, both the tank water and the waste that settles beneath the substrate turn out to be some of the most effective plant food there is.
It's packed with nutrients and beneficial live bacteria, especially when lava rock is used as the substrate in the crayfish tank. In soil-based plants and in aquaponics alike, introducing that bacteria into a system produces what amounts to "super water" for your plants. Even in an ordinary soil-based setup, water drawn from a marbled crayfish tank makes plants grow noticeably better. In a circulating aquaponics system, introducing that same bacteria has both an immediate and a long-term effect on both fish and plants.