Due to scientific evidence that fish feel pain in their lips and the regions around them, I do not agree with this.
http://news.bbc.co.uk/2/hi/science/nature/2983045.stm
http://www.cnn.com/2003/WORLD/europe/04/30/fish.fear/index.html
While the fish may not mind the "labret" studs now (after the fact), the point IMO is that you put your animals through stress and pain for personal enjoyment.
I don't think that there is an increased risk of early death or infection due to quick healing, Melafix, etc. But how is this different from taking a dog, holding him down, and cutting off the tip of his ear with scissors? Sure, you can put on antisceptic, properly bandage the wound, etc. and the dog won't know anything happened in a couple of days. But that doesn't negate the fact that you're harming your animal for a reason that is completely unrelated to that animal's health and well being.
Just my opinion as a pierced/tattooed human.
Edit and ps - I don't fish, in case anyone is wondering.