all koi are dark almost black when hatched. the photos others are posting are koi fry that are older and starting to come into color. When hatched they are very dark color.
Depending on what the parents genetics are will determine the fry colors no two are exactly the same. Some colors like yellow will not come out until later.
As the one photo shows on a previous post these koi are a few months old.
When they are new hatch Koi have no swimbladder, no mouth or vent. They will breathe by absorbing oxygen through their blood capilaries that surround the yolk sac, which will still be attached to the gut. It is essential that there is plenty of oxygen in the water, they will seek shelter as well and attach them selves to what ever they can until the egg sac has been absorbed.
