Zebra Danios is a popular hardy and interesting fish in Aquarium World like guppy. And They are very active fish, which should be kept in a group of six minimum and they require a large place for swimming. They will mostly occupy a top layer in the aquarium.
They have contributed a lot to science because of their hardiness and easy breeding capabilities for embryo growth and neuroscience.
And another interesting factor is they choose a partner for lifetime.