Midas and red zebra in a 55 gallon?

Ok, about 1 year ago, I bought a juvenile midas to put in an empty 55 gallon tank alone. About 1 week later, I noticed a juvenile red zebra being pestered to death by another red zebra in my 55 gallon red zebra tank. I had no where else to put this fish where it wouldnt be immediately killed, so I took a gamble and put him in with my midas I had just got, mainly because the midas was a juvenile and was new to the tank so wouldn't be as territorial. I was right and the two grew up together. Now, a year later the midas is 10 inches and the red zebra is 3 inches, and they are living happily together. I really expected the red zebra to die within a couple of months. The zebra could easily be eaten by the midas, but the midas doesn't do it. I don't observe any territorial disputes, and they swim side by side on both sides of the tank. So, now you understand the story, I actually have a question: How long will this arrangement last, will the red zebra ever get eaten??