nah, just let him be, maybe if he is getting bullied, do some switching... It will grow back. I had a blue acara who had more than half his tail bit off by a JD, and it recovered almost completely in a few months. Only bad thing is that when they regrow their tails, it takes a while to get the color back. He was a beautiful dominant male, but after that experience it tooka a while to get his color back.