Your digital Koi, lives forever

Spawned in the spring when water temperatures hit around 65°F to 70°F (18°C to 21°C), a single female can release hundreds of thousands of sticky eggs. They cling to pond plants and rocks. The translucent eggs incubate for roughly 3 to 7 days depending on water warmth. Sadly, they are a delicacy in the pond — adult koi (including the parents) will readily eat them if they aren't protected.

When they first hatch, they are called fry and are only about 5 millimeters long.

First 2-3 Days: They cannot swim well and have no developed mouth. They use a tiny sticky pad on their head to attach to plants and survive entirely on their remaining yolk sac.

Free-Swimming: Once the yolk is gone, their swim bladder inflates, and they rise to the surface to gulp air. They start hunting microscopic nutrients like algae and rotifers.

Once they reach about 1 inch (2.5 cm) in length, they look like miniature fish and are called fingerlings. This is a thrilling stage because their scales form, and their distinct colors and patterns finally begin to show. They grow incredibly fast during these months, switching to a diet of small insects, larvae, and crushed koi pellets.

At this point, the koi are growing at a rate of roughly 0.5 to 1 inch per month. They are strong, agile, and highly active. While they look like miniature adults, they are putting all of their metabolic energy into frame development and structural growth rather than reproduction.

Koi reach sexual maturity around age 2 to 3 for males, and age 3 to 4 for females. They are typically 10 to 12 inches long at maturity, but they won't stop growing there. A well-cared-for adult koi can comfortably reach 24 to 36 inches in length.