Personally, I have no desire to have a tattooed fish, BUT we declaw our cats, dock the tails and ears of our dogs and Lord even circumcise our children with no sedation, so I really don't see the difference! It's silly and senseless, but really does no more harm than the things mentioned above which are done are a very regular basis. My main concern wouldn't be so much with the discomfort caused doing it, but if there are any long-term effects on these sensitive creatures from the dye.