Once upon a time a school of neon tetra's used to live with Justice, but they kept dying from random diseases. So Justice was once again alone. But then a new friend appeared. A loner and a fighter... Phoenix. And Phoenix has survived the initial outing (which is why he earned a name).
Phoenix's name is fairly obvious, but why is he named Justice? Your guess is as good as mine... although mine is right since I named him. If you want the answer, think "stupid puns". You'll figure it out sooner or later. If not, email me and you can groan in horror.