Koi fish are a big commitment. Between the pond, the maintenance, and koi’s tendency to live a long life, your fish friends will require a lot out of you! But an even bigger commitment is a koi tattoo. Tattoos have skyrocketed in popularity in recent years. Over a third of millennials are now inked. Every year, the tattoo industry makes over $2.3 billion. And with the koi’s popularity upsurging in recent decades, it’s no surprise that koi tattoos are in such high demand.